Same word as encrust:

begrime, besoil, blacken, blotch,blur, botch,coat,contaminate,corrupt,debase,decay,defile, discolor, draggle,encrust,foul, grime, make dusty, make impure,mess up,mold, muddy, pollute,rot, smear, smirch,smoke, smudge, smutch, spatter,spoil,spot,stain, sull