Cleanin supplies.

I have a 97 astro w/4.3L V6.I havent used it in a while,so I decided to today.I checked the oil and whatnot.Then I checked the air filter.I was shoked to find that the filter was rusty,ripped,and pretty much coroded.As I lifted the filter I saw that the rust had spread to the plastic.So I went to buy a new filter and I have it here in hand.My question is,what is the best way that I should remove the rust?.I dont want to damage anything important in there,and I dont want to let anything seep in there again.Any sugg.?