CA glue

[Newton Hunt]

That depends upon how long you have them open.  A couple of
months can be a long time for an opened container, but...

THey thicken because of moisture that gets into the bottle
so open them a rarely as needful, keep them sealed as well
as possible, keep them dry (get some of that desiccant stuff
from piano dealers for your container), use the smallest
hole possible, when the thin becomes thicker use it as
medium or thick (same glue just thicker), do not use
anything to plug the holes only the caps, don't stick
anything into the holes use CLEAN dry clippers to cut the
tips.

By now you get the picture.  It is contaminants that begin
the setting process so keep it clean.  It is not cheap stuff
so the better you can keep it the better it will serve you.

Lots of luck.

		Newton