Another alternative to mineral spirits worth considering is Xylene. It evaporates far more slowly than either paint thinner or gasoline. Costs a little more than paint thinner but might be worth it.
Also, for removing splattered on paint, nothing works much better than acetone. I like it because the smell brings back memories of my model airplane fuel days. A little goes a long way.
Xylene works well. Iv been playing with a mixture of mean green and denatured alcohol. Its doing very well on the baked on stuff. Hasn't hurt any plastic either