Yeah, I would use cool water, and it's okay to use laundry detergent, as long as it's all rinsed out well. If you have some oxiclean (ya know, the kind that billy mays used to sell on tv) you can throw that in there and it usually does the trick. Just like your usual laundry, just a really small load, and in cold water.
i use a spray bottle and soak it in a 1:15-20 bleach solution, wait five mins, then rinse with water, dry with a towel/air dry. sometimes i use a product called wipe out, sold in pet stores.
I soak and scrub with stiff brush, I got tired of it so Now I use paper towels, also try a litter box, in the poop area. I got my big group 1.4 in a 40 breeder all pooping in a med corner water dish filled with sand. There are a few slight misses here and there but most of the tank is spotless all of the time.