I just purchased the little foam balls where the rubber band is used to keep the indicator in place, and I was very impressed. They don't cast quite as well as the Thingamabobbers, but they stayed put with absolutely no slippage and you could even move it up and down the tippet with ease.
I will try the aquaseal on the Thingamabobbers. I did try one of the rubber bands from the other indicators I just got and that didn't work well, but I feel if I get a little larger rubber band piece I will be in business.
"Give a man a fish and he will eat for a day. Teach him how to fish and he will sit in a boat and drink beer all day." ~Unknown~