Originally Posted by
Bill Kapaun
Push the air out of the glue tube before you put the cap on.
Waste a drop and it'll stay fresh(er).
This works. Also, what I do is buy quantities of the small tubes from eBay or other online sources so I have a few on hand at home. I always have a fresh/sealed one in the saddle bag for on the road use** If I happen to use it on the road, I do cap it off like he says above, but leave it at home for use there and put a new fresh one in the bag. I'd rather have a potentially dried out one at home than on the road.
** And I rarely actually use the glue on the road. 999 times out of 1000, I just get one flat on a ride. I simply use in the spare tube on the road and patch the old one at home with a tube of glue at home, virtually never patch a tire on the road. I then put the patched one back on the bike and put the non-patched one back into the saddle bag so i know that the one in the saddle bag doesn't have any patches in it.