Pollen has a relatively short viable life span - roughly 24-48 hours depending on the plant - and is easily affected by the ambient air temps and humidity. So any long term storage in anything but a controlled lab environment is quite difficult, if not impossible.

But hand pollination is easily done and quite successful, especially with the squash/pumpkin varieties. So many of us use row covers for the plants to protect them from any pest damage and then do early morning rounds of hand pollination as the blooms make themselves available. Results in no pest problems and often 2-3x the fruit production. There is a FAQ here on how to hand pollinate.

Dave