Any tips on getting good scans of transparancy slides?

Okay, so, while I was on Thanksgiving break, Dad and I went through a bunch of slides my mother took, in the days of yore. I brought four home, and tried to scan them into my computer ... with disasterous results.

I was able to make these two just visible, but only after much fiddling. There are all sorts of wierd color streaks and spots that are not on the slides when I look at them straight on, and they were so dark (I had to brighten them 100% about three times in a row to make them visible).

So? you guys have any tips for me? Would it help if I put something shiny reflective (like, say, foil) behind the pics when I scan, so the light is reflected back through better? Or would that just make it worse?

Anyway, these are the two pictures that sort of came out, in case you want to see, behind cuts:

( Hey! Where'd everybody go?! )

( Flower Child squee )