Shellac, one of many wood furniture finishes, is a resin made from the lac bugs of Southeast Asia. These bugs secrete a natural resin that is then turned into a commercial product you can apply as a finishing coat to wood. Shellac has been around for hundreds of years and is still used today by fine furniture restorers.
Shellac has many advantages. It is nontoxic with no fumes, and it's safe for surfaces children and pets will be exposed to. It is easy to work with because it dries quickly and can be applied by spraying or brushing it on. Shellac also provides a hard finish and doesn’t yellow like varnish. If you need to make repairs on shellac, you can simply apply a new top coat of shellac over the old finish to get rid of scratches or blemishes. It is also a favorite of fine woodworkers because it comes in a variety of colors and can be stripped off wood with alcohol.
There are some disadvantages to using shellac as a finish as well. One of these is that anything with alcohol, such as liquor or even cologne, can blemish the finish. Other chemicals like ammonia also cause problems so you have to be careful what you clean shellac with. Heat softens the shellac, so it is best if you avoid anything putting anything hot on or near the surface. If someone sets a glass down, the condensation may leave a white ring especially if the finish has a higher wax content. Shellac does start to deteriorate after it sits in the alcohol mixture for a period of time.