begrimed
Covered in grime
Begrimed means covered with grime—dirty, sooty, or blackened from accumulated filth.
The word suggests ingrained dirt rather than a light dusting: begrimed factory windows, a begrimed face after hours in the coal mine.
It's somewhat literary, more likely encountered in Victorian novels than everyday speech.
filthy
Thoroughly unclean
mucky · smudged · unclean · dingy · caked · muddied · smeared · besmirched · fouled · grungy
blotched
Marked with irregular spots
spotted · discolored · blemished · mottled · splattered · speckled · flecked · marred · blotchy · marked
chimney-sweep
One who clears soot