Removing shellac is one the easiest types of wood finish repair jobs.
Finishing With Shellac Furniture Refinishing Studio
How To: Shellac Wood - Bob Vila
How to apply shellac as practical wood finish - Paul Sellers' Blog
Repairing Shellac/Laquer Finish - FineWoodworking
Restoring Darkened Cracked Shellac Finish on Wood - Page 2 - The Historic District
Tips on fixing and blending improperly applied shellac?
How to Revive a Finish - FineWoodworking
Woodworking Projects
Repairing Scratched Clear Coats
Removing Stains and Discoloration From Wooden Furniture: Tips
Zinsser 1-qt. Clear Shellac Traditional Finish and Sealer (Case of 4) 00304H - The Home Depot
How To Remove Sap From Wood
Cracked Finish? Here's an easy fix: Reamalgamation for Dummies