well if you get a bowl of warm water and gently place them in there (make sure the level isn't too high) you can use a wash cloth and lightly scrub them with kitten shampoo and a washcloth.
The tails are done with a soft bristled tooth brush.
They'll protest at first, so you should kinda make it into a routine thing (;
Rat Property Laws
1. If I like it, it's mine.
2. If I've peed on it, it's mine.
3. If I can take it from you, it's mine.
4. If I had it a little while ago, it's mine.
5. If you've got something larger, it's mine.
6. If I'm chewing something up, all the pieces are mine.
7. If it's in my reach, it's mine.
8. If I saw it first, it's mine.
9. If you are playing with something and you put it down, it automatically becomes mine.
10. If it's broken or it tastes bad, it's yours.....