Actually I've heard fat bumps are very common with mini-schnauzers. They seem to go away on their own though (if it is that). Although when it comes to bumps its always good to have a vet check on it just in case it might be something malignant.
I've not heard of dogs getting warts (although it may be possible), but if they do get them I imagine they are removed in the similar fashion that they are in humans...but don't quote me on that because I'm not entirely sure.