Brooke Mueller -- My Charred, Black Hands Were NOT From a Crack Pipe

Brooke Mueller maintains the black soot-like substance covering her hands last night was NOT from drug use ... just good old, fashioned spray paint (which she used for painting).

Brooke was out in L.A. Friday night -- just hours after being released from the hospital for an alleged drug overdose -- sporting some pretty nasty looking hands.

She tells TMZ ... it's not what you think. Brooke says she's been spray painting a lot for her artwork (see below) and that is why her hands were so dirty in the video.

Mueller says she's been sober for MONTHS ... but nobody seems to believe her.

So to recap ... she says her jewelry-making-bender caused her to pass out cold on Friday and her artwork made her hands black.