I use a spatula and scrape all my left over inks into containers from the art store. I prefer the ones in the back (pic above), they're a little larger. They come in a pack of 12 for about $1.99 at Michael's.
Sticky pad losing it's stick? Take a roller brush and remove all the tiny specs of lint and dust. Look at all the lint that came off. The stick comes back. Just as new. It's even removed paint that's made it's way on the pad.
When my image or paper is larger than the pad, I roll some fabric and stuff the hole. Creating a larger printing surface.
When I store my PG-11, I cover the pad with a sandwich bag (or any kind of plastic) keeps the stick pad clean. Since I've started doing this, my pad has stayed sticky longer.