Welding Tips and Tricks

I'm just a novice, so I've got a novice question.........

I bought a "project" that has a few 1/8' mild steel T joint welds that are "cold" and "globy". If I grind away as much of the existing MIG weld as I can: 1. Can I TIG weld over the MIG weld? or, 2. Should I re-MIG weld over the MIG?

What I need to understand regarding either approach would be much appreciated!!!

You can certainly TIg over Mig..I just did it to a grill I made when I did a couple sloppy Mig welds.. You could Mig it again too.