sure looks like clear lacquer to me)
soap, suds, warm water, laundry tub, Real Lightly run over it with (soaked pad of) #0000 steel wool LIGHTLY..
if anything bad happens don't call me but
I clean a few of my old Ks that way.. so
buy a bag of #0000 (number 4 only) wool steel.
give it a light wash.