Ways to take off layer of spray paint?

[12secondnova]

Like the title says. Previous owner spray painted over parts of the truck with a different blue and it has runs everywhere. Anyone know of a safe way to take that off? Eventually its going to get painted but I wanted to see what I could do with the current paint its got so I could focus on drivetrain first. Definitely know its not going to turn out perfect but it figured id give it a try. Any help or suggestions/directions on how to do this is greatly appreciated!

Heres some pics to give you an idea of the paint.