PVC Pipe Solvent/Cement, How do you Prolong in storage ?

I've never bothered trying to prolong the life of PVC / ABS cement which I can buy in small cans as I may need it but with larger containers of paint, drywall mud, etc, I find that placing a layer of clear plastic film over the top surface of whatever is remaining in the can goes a long way to preserving the contents in it's original state. I've used drywall mud and paint several years after original purchase and it's been just as good as when I bought the container new.