If its moisture or residual solvent you can probably dry it out by warming it up and either using a vacuum or a dessicant like damp-rid (calcium chloride).
However if its rxn by product, your best chance is to perform a freezing anhydrous acetone wash. It's easier than it sounds.
Get some acetone, and put in some sort of anhydrous sulfate salt (baked epsom salts work) let it sit in freezer overnight. Crush the 2cb as best as possible and place in coffee filter, filter out the dessicant and run the acetone over the 2cb powder. This will remove a lot of garbage.. you could further purify by dissolving the powder in boiling anhydrous isopropyl and either stick in freezer or let it very slowly cool and evaporate.
I'm guessing based off of color that you have the hydrobromide salt. If you purify it enough it will be snow white.