if its grimy like i would assume being thread worthy... here is what we did
We had a funnel with gunk in it for over a month. It was a really nice funnel valve clear1inch tubing everything ... and i wasn't going to through it out.
Pour some baking soda in it, then poor in a bunch of vinegar. it will make a crazy reaction. let it sit for an hour, rise it out. repeat if necessary. Once you think its cleaned out (usually 1 or 2 times does the trick) send hot water through it for 10 minutes or so. Comes out brand new, no bad taste at all