MIMF

I have a question about (re)finishing a guitar.

After stripping a polyester finish and sanding the factory base coat and sealer, is it necessary to use a solvent like NAPHTHA to ensure that there are no remaining contaminants on the wood surface?

Can I go straight to sealing with shellac?

Any help is appreciated.

Shellac is compatible with most everything and should be fine without the cleaning step. However, there is the risk that someone used a silicone polish on the guitar at some point and this could cause problems, so a naphtha cleaning would not hurt anything and might prevent a problem down the road.