Try closing a small box and cutting a few small holes in it. (cattime.com)
Let that bubble for a half hour, which is about the time it took me to realize I don't own a fine - mesh sieve, feel panic, then dig up some cheesecloth (or anything with small holes in it). (bonappetit.com)
The knit does tend to get small holes in them after a long time (a couple years of use), but they don't run so I'm still using ones with holes of them, going on year 4 of diapering. (amazon.ca)