empty them a day or two after chop
let them dry completely
take them outside, knock off any big chunks, pull off all dry roots
hand wash, scrub w/ soap in 5 gal bucket
refill bucket w/ water& give them a good rinse
let dry
Yes, this is a PITA but I don't want a washing machine full of coco bits. It probably won't help if you use large smartpots, but I've found that 9x9 square netpots are fairly equivalent to the 2 gal smartpots and will air-prune just as well and grow plants just as big. They're also far to clean & reuse and cheaper too. All netpots for me next run.