How can I get a lot of raritarium in Ratchet and Clank : Going Commando?

I need a way to find lots of raritarium so that I could get all the upgrades for my ship. Right now I'm on the level where you have to rescue Angela from the Thugs. I already did the drilling thing on the desert level. Are there any other ways to get raritarium? Also, on the desert level, will the raritarium come back so that I can drill for it again?