I put mine in the dryer after washing with my regular laundry.
Fabric softener shouldn't be used on them, but I don't use it anyway. Don't wash with towels, though, because they'll pick up the lint from the towels.
I don't use them for dishes or for anything that I use an abrasive cleaner (like baking soda), but I use them for pretty much everything else -- mirrors, windows, walls, counters, TV or computer screen, dry dusting, anything that just needs wiped down, non-porous toys, etc. Oh, I don't use them in the kitchen, I use the regular washcloths there because I have so many. I use them mostly with water or a vinegar/water/EO mixture, depending on what I'm cleaning.