I'm not sure if this is a good thing to do or not, and I would wait for someone else like.. GaGrown to confirm that this strategy isn't dangerous at all... but I will tell you what I did.

When I was transplanting mine, I took a spray bottle with water and sprayed down the root ball a little bit. This cleaned off some of the roots on the outside and allowed me to trim a little bit better, also I kinda figured it allowed the outer roots to have better access to the new soil (which was the same soil type as the old soil, I think that is important). It worked well for me, but again, please check around with other more experienced people before you do this.