the sponge he used was one of those "mr. Clean" pads that are excellent for removing all sorts of dirt, however, they only remove surface dirt. For RES it's better to get a baby tooth brush and scrub your turtle weekly, that way if anything is under thier scutes you can somewhat clean it. No, they don't really like being scrubbed, but it is good to do once in a while.
I use a clean toothbrush...but just be careful as to where the heads are while cleaning!!! I got a nasty bite from Tarragon because I wasn't pay attention to her head because I was too busy watching the shell lol
Zater: Red Ear Slider
Scout: Western Painted Turtle
Rufus: Eastern Painted Turtle
Hatcher: African Side-Neck Turtle