Your LEGO collection has seen better days. Dust blankets your display sets, sticky fingerprints cover your bricks, and that bulk lot from eBay smells like someone’s basement. Don’t worry—cleaning LEGO is straightforward once you know what works and what could permanently damage your precious bricks.
The quick answer: Hand wash LEGO in lukewarm water (under 104°F/40°C) with mild dish soap. Scrub gently with a soft cloth or toothbrush, rinse thoroughly, and air dry on a towel. Never use hot water, dishwashers, dryers, or harsh chemicals—they can warp, crack, or discolor your bricks.
Why Proper LEGO Cleaning Matters
LEGO bricks are precision-engineered from ABS plastic to connect with satisfying tightness and hold together during play. According to LEGO’s official guidance, the dimensional accuracy of each brick is within 2 micrometers—that’s why genuine LEGO feels better than knockoffs.
The problem? That precision makes LEGO surprisingly vulnerable to heat damage. ABS plastic begins to deform at temperatures above 104°F (40°C), which means hot water, dishwashers, and tumble dryers are all potential brick killers. Once warped, a LEGO brick never connects properly again.
Beyond heat, certain cleaning chemicals can weaken the plastic, cause stress fractures, or fade colors over time. With proper care, LEGO bricks last decades—my oldest pieces are from the 1990s and still connect perfectly. Careless cleaning can ruin them in a single afternoon.
The Best Way to Clean LEGO Bricks (Hand Washing)
Hand washing is the safest, most effective method for cleaning LEGO. Here’s exactly how to do it:
What You’ll Need
- A clean basin or bucket
- Lukewarm water (test with your wrist—it should feel comfortable, not hot)
- Mild dish soap (Dawn, Fairy, or similar)
- A soft cloth or sponge
- A soft-bristled toothbrush for stubborn dirt
- Clean towels for drying
Step-by-Step Process
- Separate pieces if necessary. For assembled sets you want to keep built, skip to our section on cleaning without disassembly. For loose bricks, proceed to washing.
- Fill your basin with lukewarm water. LEGO officially recommends water no hotter than 104°F (40°C). When in doubt, go cooler.
- Add a small amount of dish soap. A few drops is plenty—you’re not creating a bubble bath.
- Submerge your bricks. Let them soak for 10-15 minutes to loosen dirt and grime.
- Gently scrub each brick. Use your soft cloth for most pieces. For stubborn dirt in small crevices, use a soft toothbrush with light pressure.
- Rinse thoroughly with clean, cool water. Soap residue can leave a film that attracts more dust.
- Spread bricks on a clean towel to air dry. Flip them once during drying to ensure no water gets trapped inside.
This method works perfectly for routine cleaning and for sanitizing secondhand LEGO. In my experience, even heavily soiled thrift store finds come out looking factory-fresh.
Cleaning LEGO Sets Without Taking Them Apart
Sometimes you don’t want to disassemble your meticulously built display sets. Here’s how to clean them while keeping them intact:
Dry Dusting Methods
Soft-bristled brush or makeup brush: The gentlest option. Use a clean, soft brush to sweep dust from surfaces, working from top to bottom. A makeup brush is perfect for getting into tight spaces.
Compressed air: Hold the can upright and use short bursts from about 6 inches away. This blasts dust from hard-to-reach areas without touching the model. Be gentle with fragile sections.
Vacuum with brush attachment: Use low suction and a soft brush attachment. Keep your hand nearby to catch any pieces that might get pulled loose. This works well for larger display sets.
Gentle Wet Cleaning
For dusty sets with some grime, dampen a soft cloth with plain water and carefully wipe surfaces. Don’t saturate the model—you just want to collect dust, not soak the set. A microfiber cloth works particularly well here.
For really good results on large display sets, consider investing in a small handheld steamer. Steam cleaning loosens dirt effectively and the moisture evaporates quickly. Just keep the steamer several inches away from the LEGO to avoid heat damage.
Cleaning Different Types of LEGO
Standard Bricks and Plates
Regular ABS plastic bricks are the most forgiving. Follow the hand washing method above, and you can’t go wrong. They’re durable enough for the soft toothbrush treatment without concern.
Printed and Decorated Pieces
Printed elements (faces, dashboards, signs) require extra care. The printing is generally quite durable, but avoid scrubbing directly on decorated surfaces. A soft cloth with gentle wiping motions is safer than a toothbrush.
Never use rubbing alcohol or harsh chemicals on printed pieces—these can dissolve the printing. Stick with mild soap and water only.
Stickered Pieces
Stickers are the most vulnerable LEGO elements. Water can lift edges and cause peeling. For stickered pieces:
- Avoid submerging if possible
- If washing is necessary, keep submersion time very short
- Don’t scrub directly on stickers
- Air dry with sticker side up
Transparent and Chrome Pieces
Transparent pieces show scratches easily. Avoid toothbrushes and stick to soft cloth only. Chrome elements are even more delicate—light wiping with a damp cloth is the safest approach.
LEGO Technic and Electric Components
Motors, battery boxes, lights, and other electric components must never be submerged in water. Wipe these with a slightly damp cloth and dry immediately. For Technic gears and axles, a dry brush works best.
Minifigures
LEGO minifigures can be hand washed, but consider disassembling them first (remove heads, hats, accessories). This lets you clean inside the head cavity where dust accumulates. Be gentle with printed faces.
How to Deep Clean Used LEGO
Buying secondhand LEGO is great for your wallet but sometimes challenging for your senses. Here’s how to tackle truly grimy bulk lots:
Initial Sorting
Before washing, remove:
- Non-LEGO items (other brands, random toys)
- Electric components
- Heavily stickered pieces (wash separately)
- Severely damaged or melted pieces (discard)
The Soaking Method for Bulk LEGO
- Fill a bathtub or large container with lukewarm water
- Add dish soap and optionally a splash of white vinegar (helps with odors)
- Submerge your LEGO and let soak for 15-30 minutes
- Agitate the bricks periodically by stirring gently
- Drain, refill with clean water, and rinse
- Spread on towels to dry completely (this can take 24-48 hours for large batches)
Dealing with Stubborn Issues
Sticky residue: Goo Gone or similar adhesive removers work, but test on a non-visible piece first and rinse thoroughly afterward.
Smoke smell: A vinegar solution (1/4 cup white vinegar per gallon of water) helps neutralize odors. Multiple washes may be necessary.
Marker or pen marks: These are often permanent, unfortunately. You can try a Magic Eraser with very light pressure, but this may leave marks on shiny surfaces.
Restoring Yellowed LEGO Bricks
Older white and light gray LEGO often develops a yellow tinge from UV exposure. This discoloration is caused by a chemical reaction in the ABS plastic and can be reversed using hydrogen peroxide.
The Hydrogen Peroxide Method
- Sort out all yellowed white/light gray pieces
- First, wash them normally with soap and water
- Fill a clear container with 3% hydrogen peroxide (standard drugstore strength)
- Submerge the yellowed pieces completely
- Place the container in direct sunlight (UV light activates the whitening process)
- Check progress every few hours—this can take 1-3 days depending on severity
- Once whitened, rinse thoroughly and dry
Important safety notes: Wear gloves when handling hydrogen peroxide. Don’t use concentrations higher than 3%. Keep pieces submerged and out of reach of children and pets.
The results can be remarkable—I’ve restored 30-year-old pieces to near-original whiteness. However, extremely yellowed pieces may never fully recover, and some discoloration can return over time with continued UV exposure.
What NOT to Do When Cleaning LEGO
These common mistakes can permanently damage your bricks:
Never Use Hot Water or Heat
This is the single most important rule. Hot water, dishwashers (even on gentle cycle), tumble dryers, and hair dryers can all warp LEGO. Even brief exposure to high heat can cause subtle warping that affects connection quality.
Avoid Harsh Chemicals
Stay away from:
- Bleach (can discolor and weaken plastic)
- Rubbing alcohol (can cause cracking, removes printing)
- Acetone or nail polish remover (dissolves ABS plastic)
- Abrasive cleaners (scratch surfaces)
- Strong solvents (weaken plastic)
Don’t Use Ultrasonic Cleaners at High Settings
Ultrasonic cleaners can work for LEGO, but only on gentle settings with cool water. Aggressive ultrasonic cleaning can loosen printed elements and damage fragile pieces.
Never Bake or Microwave LEGO
It sounds obvious, but some people have tried “sanitizing” LEGO in ovens or microwaves. This will destroy your bricks.
Keeping LEGO Clean Long-Term
Prevention is easier than cleaning. Here’s how to keep your collection pristine:
Display Cases
For valuable or detailed sets, display cases are worth the investment. They keep dust out completely and protect from UV light that causes yellowing. Even simple acrylic cases make a huge difference.
Regular Dusting
A quick weekly dusting with a soft brush prevents buildup. It’s much easier than periodic deep cleaning. Make it part of your routine.
Proper Storage
For stored LEGO, sealed containers keep dust and moisture out. Clear bins let you see contents without opening. Avoid storage areas with temperature extremes or direct sunlight. For tips on organizing large collections, check our guide to building toys by age which includes storage recommendations.
Clean Hands
Simple but effective: wash hands before building. This prevents transferring oils, food residue, and dirt to your bricks.
Frequently Asked Questions
Can I put LEGO in the dishwasher?
LEGO officially recommends against this, and for good reason. Even “gentle” cycles often exceed safe temperatures, and the water pressure can damage fragile pieces. Stick with hand washing.
Is it safe to wash LEGO with bleach?
No. Bleach can discolor bricks and weaken the plastic over time. Mild dish soap is all you need for sanitization.
How long does LEGO take to dry after washing?
Small batches dry in a few hours on a towel. Large bulk washes can take 24-48 hours to dry completely. Make sure pieces are fully dry before storing to prevent mold or musty smells.
Can I wash LEGO Technic sets?
Standard Technic pieces (beams, pins, gears) can be washed like regular bricks. Remove and set aside motors, battery boxes, and electronic components—these should only be wiped with a slightly damp cloth.
Will washing damage printed LEGO pieces?
Normal hand washing with mild soap won’t damage genuine LEGO printing, which is quite durable. Avoid scrubbing directly on prints and never use alcohol or harsh chemicals.
How do I remove permanent marker from LEGO?
Unfortunately, permanent marker is often truly permanent on LEGO. You can try a Magic Eraser with very light pressure, but this risks dulling the surface finish. Sometimes replacement is the only option.
Can I sanitize secondhand LEGO for my kids?
Yes! Hand washing with dish soap effectively removes dirt and germs. For extra sanitization, add a splash of white vinegar to your wash water. Rinse thoroughly and dry completely before use.
Final Thoughts
Cleaning LEGO doesn’t have to be complicated. For most situations, lukewarm water, mild dish soap, and patience are all you need. Avoid heat at all costs, skip the harsh chemicals, and your bricks will stay in perfect condition for decades.
Whether you’re maintaining a pristine display collection or rescuing a grimy thrift store haul, proper cleaning techniques make all the difference. Your LEGO investment—both financial and emotional—deserves that care.
Now get those bricks sparkling and get back to building! If you’re looking to organize your freshly cleaned collection, our guide to LEGO car sets might inspire your next display project.
