I started fly tying last winter and picked up some Dave's Flexcement from Umqua to finish my heads off with. Now I have not tied anything since last February. The other night I went to tie some flies and the cement was the consistency of wax, It would not seep into the threads. Now I had the cement with the lid tight in my basement all summer. The container it came in had both a plastic cap and a rubber gasket that I assume was meant to be used with a bodkin.

What did I do wrong? Can I fix it? How do I stop it from happening again?