Rust spots on SS keg

Whoever it was that welded the fittings on my keg must have used regular steel wire instead of stainless. The welds are well-rusted. Not only that, but there are weld spatter spots on the inside and outside of the keg that have rusted.

I'm thinking I might just try to sand down the rusted weld spatter to get down to bare SS again. Is that likely to work, or will it just damage the keg or spread the rusting steel over a wider area?

http://www.mmsonline.com/articles/100304.html that covers it all or there is always : http://www.howtobrew.com/appendices/appendixB-1.html

Thanks for the links. I have Bar Keeper's Friend, so I'll try that to remove the rust. I also have more concentrated oxalic acid in my darkroom that I can try if the BKF doesn't do the trick. But I still think I'll have to grind off the weld spatter.