I agree with tobuluv, spaying/neutering is necessary if possible. I know it can be pretty expensive in some places, but it’s worth it.
As for a bath, I have found that baths are not as dangerous as most people say (absolutely no offense to anyone who says otherwise, if you do not wish to take my advice, then I will not be insulted. Bathe your bunny at your own risk but I recommend not bathing any bunny under at least 7 months). The most important part is making sure they get dry and keep the water very warm or else the cold will shock them very badly and make them sick or kill them. However, depending on the age of your rabbit, bathing is okay.
Before bathing him, make sure you try the other dry-cleaning methods people suggest, as they are safer. If none work, you could consider bathing. Just, like I said, make sure the water is nice and warm and he gets dry very quickly and very well.