jamesepworth:
Personally I never use varnish, shellac, or anything similar. I'll be interested to read what any pipe-makers here on the Forums have to say concerning this.
If the wood is colored and needs touch-up, then I will use Fiebing's leather dye cut with grain alcohol (190-proof Everclear). Do this carefully, as Everclear is highly flammable. I apply the dye/alcohol mix and then, while it is still wet, seal it in by igniting it briefly with a butane lighter. This is a trick which I learned from an article by Robert Cooper, and it works well for me.
I typically polish the unfinished wood using my bench-top buffer (taking care to avoid any stamped nomenclature), and dress the wheel with tripoli for the initial passes. Final passes are performed using a wheel dressed with red rouge. For waxing I use Carnauba, and buff at slow speed using an undressed wheel.
I hope that you find this information to be useful.