I would think deposits would cause your bike to run lean, not rich. They would constrict the jets if anything, not make them flow better.... unless the deposits were in your air hole for the airscrew (but that would be unlikely), then it may run rich at low speed, but should still be real close to ok at higher speed.
I question the logic behind what your local shop had to say... spooge is the result of too rich... if you get your jetting nose on, and everything else is in good shape you will not make much spooge if any. BUT, even if you jetted right and didn't repack the silencer (if your silencer is repackable) you will still see residual spooge untill it dries up.
Jetting is an easy task, I suggest you tackle it yourself unless you are very unconfident in your work.
I bet it will still spooge until you correct the jetting.