I haven't heard the one about mattress stores. The one about laundromats is plausible, but you aren't going to be able to launder much money through a laundromat. They may be an almost exclusively cash business, but it's not as much as you think.

I work at a bank, and the laundromats we work with bring in less than 1000 a week. The guy who owns the laundromat also has vending machines and a car wash that is included in the deposit. If they suddenly started bringing more than that, us bank tellers would immediately be suspicious. A mildly successful restaurant will easily bring in 1000+ a day in cash, it would be less suspicious if a restaurant was bringing in larger quantities of cash than usual, especially if they said something like their card reader is broken or they have some special that is really taking off.