How do you know when you've run out of invisible ink?

Question: How do you know when you've run out of invisible ink!?
Best Answer - Chosen by Asker:

when u write on paper and nothing comes outWww@QuestionHome@Com

as soon as you get to yahoo answers cause it just blends in and becomes invisible again!.Www@QuestionHome@Com

YOUR OUT! Just thought you might want to know so you can get more!. Www@QuestionHome@Com

It turns invisible after it dries on the paper!.Www@QuestionHome@Com

the paper doesn't appear wet or feel close to having writing on it -_-Www@QuestionHome@Com

I have no idea!!!! My Goddess this question will torment me all night!.!.!. thanks a lot!!!Www@QuestionHome@Com

wen u look at it under a black light an it is not there Www@QuestionHome@Com