OK, calm down! My stilo has no rust!
But my wife's old rover 25 has a few rust bubbles that need treating, mainly in the gutters on the roof (leaky sunroof meant water had gathered there). I'm asking on here coz the Rover forums are full of numpties!

Now I'm no expert, and have very little patience or skill at these things, but I reckoned I should sand them back, rust kill/prime, then slap on a bit of paint to make them look half decent prior to probably selling the car - got to be worth a few hours to get £600 instead of $350, hopefully.

So I picked up a detail sander at the car boot for a fiver at the weekend, and I now need some paper to put on it, I want to knock off the bubbled paint.. so what paper should I use and what grades? I don't need a perfect job, but would like to get it looking clean enough to the naked eye...