Do whatever you please with dryer sheets in your personal laundry room, but remember the laundromat is a public place. Used fabric softener sheets, empty bottles of detergent, the fuzzy residue from the dryer's lint screen; these all belong in the trash, not on top of the machine, in the machine, on the floor or wherever else laundromat patrons might be leaving them. In short: Don't be a litter bug.
Additionally, let's talk about carts. Don't let your laundry cart etiquette upset the apple cart. (Translation: Put items such as carts back where you found them or risk upsetting the laundromat regulars.) There are two basic types of carts you'll find in the laundromat: the large rolling baskets and the laundry butlers (those are the large rolling baskets equipped with a pole and bar above for hanging clothes). Naturally, if you have clothes you'll need to hang, you'll need the laundry butler. But if you don't have anything to hang, do we have to say it? Leave the butlers behind for those who need them. Not only is it good karma (one day you, too, will need the laundry butler), it's good manners. And when you no longer need the cart, return it to its rightful spot — which we're pretty sure is not the aisle.