I don't know about the bacteria... I was wondering out loud hoping one of our experts would chime in. But I don't think removing the 5 day old skin will harm him any. I've had to pick all kinds of stuff off my white's (I have 3)
Today I had to give my littlest one a bath/shower because he got out and was lost for a few hours. He had dust/dirt and hair all over him. I guess we need to dust under the bookcase more often. Poor guy, but he's good now.