Imagine coating your guitars’ rosewood back and sides with almost black mud! That’s what allows your instrument that glass-like lacquer finish, giving the grain such three-dimensional depth. The paste filler is painted on with a brush; after drying for about an hour the filler is wiped off with burlap cloth, leaving little residue except what fills the pores of the wood grain. Any smudges, etc. are wiped off with cheesecloth.