After a cocaine snorting session, my friend will blow his nose, open up the tissue, pick out the white chunks and put them on his tongue. He does this to determine if the white chunks in his snot are simply insoluble cuts, or bits of cocaine that weren't absorbed due to his capillaries / membranes reaching full capacity and becoming unable to absorb anything for a while. Most of the time, the chunks DO numb his tongue leading him to believe that it is actually cocaine that just wasn't / couldn't be, absorbed....