You might want to try this product. I have used it for small scratches and it does a very good job, but I had very small scratches so I think it will depend on how deep they are. http://www.janvil.com/glass_revive.htm
if its on the inside of your tank, i would leave it...i think using a buffer/drill or something may make the tank slightly weaker and also not sure how to describe, but where you 'buffed' the view may be slightly impaired, like a smudge..