Dewaxed shellac is free of wax, which makes it perfectly clear when dissolved in denatured alcohol. It can be used as a sealer or as a barrier coat to eliminate odors in old furniture. Being dewaxed, it is compatible with oil and water-based lacquers and varnishes.
On the other hand, waxed shellacs contain a significant amount of wax, which makes them slightly cloudy once dissolved. The wax they contain also makes them incompatible with lacquers and varnishes.