Turns out you really can put Legos in the washing machine.
Why would you want to? Well, mine have been living in the garage until last month.
Water alone isn't enough to get off the dust/grime. I washed a few batches in a dishpan filled with warm water and dish soap in the sink, jostling the whole concoction (scrubbing with a tooth brush when needed) and then rinsing off bits in a colander. Pretty time consuming.
Hence, washing machine.
I'm sorting out pieces with stickers, printing, metal or electric bits, and tires to do in the sink later. The rest I stick in a mesh lingerie bag for the machine.
My washing machine has a small load basket which sets inside of it so I'm using that. Warm wash/cold rinse, gentle cycle, laundry detergent. Surprisingly, it's not even loud. Might get more of a racket with no small load cylinder thing though. You could always try throwing in a few clothes to muffle the sound.
When the wash cycle is done, I shake out excess water from the Legos in the bag and then I lay them out to dry. I haven't noticed any color loss. There may be some scratching from the pieces hitting each other in the wash, but it's not like mine were mint pieces to begin with. One piece with printing on it that got past me also turned out fine.
Note the yellow and white pieces don't get as refreshed-looking as the other colors post-wash. The plastic doesn't age as well with the white, so sometimes there's yellowing that doesn't come off.
Not sure what I'm going to store them all in once I'm done, but for now, I'm sorting them into various containers I have around as I go. Keeps me out of trouble.
Anyone have any great Lego sorting techniques/methodologies?