How to use wash LEGO pieces in a laundry machine

We do not guarantee your results or that you will not damage your LEGO pieces or your dish washer. Like any new skill you learn on the internet, check multiple sources and form your own intelligent opinions and then proceed with caution.

We have been washing LEGO pieces in the laundry machine for many years and wash at least 100 lbs a week this way. We selected a machine whose drain holes are smaller than a LEGO lightsaber or bar piece so it was less likely we would damage it if a mesh bag tore open. We also picked one with no beater bar so we could load the bags in and out more easily. 

It is important to not wash certain pieces in the washing machine.

We do not wash large pieces that have a longest length longer than 16 studs and do not wash 8x16 or larger plates in the laundry machine. These larger pieces tear up the mesh bags and get cleaner in the dish washer. We wrote an article on that as well.

We do not wash printed or stickered pieces in the laundry machine, at least not on purpose. We have plenty that sneak through and seem unharmed. We prefer not to risk it, though.

We do not wash larger transparent pieces or tiles in the laundry machine as they show scratches more readily. 

We do not wash minifigures in the laundry machine.

When we prepare pieces to be washed, we take every single piece apart so they can be properly washed and air dried. This includes tires off their wheels. We do not take assemblies apart that LEGO ships assembled.

We also pick out all the non-LEGO items like crayons, playdoh, paper, batteries, ink pens, candy bars, cell phones and other stuff that might make a mess of your LEGO or washing machine.

We load the pieces in large heavy duty mesh laundry bags with about (2) 5-gallon buckets full of pieces dumped in a bag that is big enough for them to spread out evenly on the rinse cycle. We then load the machine with 2-4 of these bags because we have a large machine. This is about 50 lbs of LEGO pieces in our machine.

Washer settings.

We use the hottest water settings. LEGO recommends less than 104°F / 40° in their article linked below - probably because they do not want you to sue them over getting burned. We do not interact with the water during any step, so we go as hot as the machine will provide from the water heater. 

We select the delicate setting and the deep fill setting. We also select the double rinse setting.

If the pieces are extra dirty, we might select the presoak or extra rinses or both.

For a cleaning agent we use concentrated white vinegar. We don't like the long list of chemicals in most soaps and detergents, and we do not want our LEGO pieces to smell like anything when it is cleaned.

Interestingly, LEGO specifically discourages washing their products in a dish washer, but that is probably because they don't want to deal with people who don't read instruction and then complain loudly.

Here is their article on the matter: https://www.lego.com/en-us/service/help-topics/article/cleaning-your-lego-bricks