David Damerell writes:

I saw a friend riding the other day, and we were discussing what to
carry on a ride. He mentioned, "A patch kit, and two tubes of
glue. One that hasn't been opened, ..."

I bring a spare tube. The patch kit's just for emergencies.

We laughed, and went on our way. But how does anyone keep the
darned tube from drying out (or actually evaporating, I guess)
between flat repairs?

The opened tube from a Rema Tip Top patch kit on my bike, which has
been open for a few years, has not dried out. Ditto the one in my
toolbox.

Well! I guess that proves that it cannot occur. So what other
explanation do you have for dried out glue tubes, even unopened ones?

Jobst Brandt