Knotty burls have interesting colors and textures hidden inside of their gnarly exterior. They can be finished with urethane, if they are not to be used with food. This creates a glassy appearance and allows the fascinating patterns to shine through the varnish. Food grade finishes are needed for all containers that will hold fruit or other edible items. This finish needs to be reapplied after every few uses, to maintain the finish and keep the wood from drying out.
Seal all crevices and pockets with sanding dust and epoxy glue. Mix the two components to make a filler and press into the splits and cracks.
Sand the surface to smooth it.
Finish with 100 percent tung oil varnish. Tung oil is slow to cure and will appear wet as it dries.
Polish with carnauba wax. Use a soft cloth to buff the surface.