To cook, as in pu in oven with heat on,, if your just using the purpleheart for tips maybe handle, it wouldnt matter much about brittle i would think, i have a pendant that is 3 or 4 yrs old, cooked and unfinished (naked wood) its still as purple as the first day i wrkd it. Purple heart is pretty brittle to begin with ,a very dense heavy wood. Tried pics didnt wrk for me.