I always carry a 4oz bottle of solution with me (whichever one is in the green and white bottle). I toss it in the bin with my ziploc baggie (but not in the baggie) and consider that my "declaration." Maybe 10% of the time the X-Ray operator will pull the bin out, look at the bottle, toss it back in and send it on out. I have not been questioned on it in a couple of years now.
Matt