I am new to the forum but will share what I did.
I have found that over time all plastics loose moisture and become brittle. I was thinking of a way to re-moist the plastic on as deep and lasting a process as possible.
I worked at a rubber stopper manufacturer and a primary base ingredient was glycerin. I figured I would apply literally with my fingers, rubbing it in and let it sit for 5 mins. or so, then wipe down leaving the surface dry.
I then did the he
at thing and while still warm, re applied a light coat of glycerin and rubbed it in like a polish. It seems to have done the trick. I will let this coming season tell the wear characteristics and how long it lasts.
Here are the results I got.