I have a ceramic vase that leaks water very slowly. I can tell where the water comes from but I cannot get my hand inside and I wouldn't know what to use to seal it from the inside even if I could get my hand in. Is there a glue or some kind of sealant that I could squirt inside that would dry and provide a seal.

What I would do in this situation, is purchase a gloss spray polyurethane. Make sure that the vase is perfectly clean and dry by washing it by scrubbing with a dish detergent and a wand of some sort that will reach all the way to the bottom, rinse out thoroughly, then dry it with a hair dryer.

Once I was sure that the inside of the vase was perfectly clean and dry, I would then spray the polyurethane into the vase and wiggle it around gently, so that the polyurethane would settle into whatever cracks there are. Then I would wait about eight hours and repeat the process again.

This should solve the problem.