From a toy planes site - lots of good tips there:
Model Doctor #116 CyA Tip Clogs Unstuck
One of the real hassles of using the gap filling CyA's is, as always, the clogged tip on the bottle. As everyone who uses it knows. even with the best of techniques, the nozzle gets clogged long before the CyA is gone. There are several ways to solve this problem.
- Cut off the tip. Now you are rid of the clog and with that 1/4" hole in the end of the nozzle the CyA is really easy to get out.
- Drill out the tip. Same as above but now you also have a drill that is full of glue.
- Throw the bottle across the shop and go get a new one. of course, if it's 11:30 on a Friday night you can kiss off wowing them with your new Belchfire 60 at the field Saturday.
Here is a solution that will work. Buy a package of extra tips and don't mutilate the tip when clogged. Instead, put it in a tightly capped jar (baby food or olive oil), filled with acetone. Acetone will dissolve the CyA and will not affect the nozzle. The next day it will be as good as new. Make sure the tip is dry and free of acetone before installing on the bottle. Remember, acetone is a fire hazard so treat it as such. From Jeff's R/C Aviation Web Page