Definitely not. There is an olds wives tale that says you should brush them with a wire brush - ouch! But this is definitely a no-no. The best preparation is to do a bfing course, and it is often recommended that you "get to know your bbs" - ie feel them to know what they feel like empty so that you will be more in tune to them when they are "working", and feel more comfortable about touching them. Most women feel uncomfortable with this, but believe me once you've bfing for a while touching your bbs does not feel strange at all!