It depends on what the paint is. If it is latex, denatured or rubbing alcohol should work. If it's oil based, then paint thinner is probably not strong enough, though you could try it. Lacquer thinner is probably what you need, but that has a chance to ruin the finish on the grill....depends on what the finish is on the grill. Paints that are factory baked on can be cleaned with lacquer thinner usually safely. Test it first.

grill is all stainless steel on the outside

1) Do you have a Weber?
2) Is the paint/stain a big "smear", or more "spotted"?
3) Is the paint a product you have, or someone painting for you? Check the can if you had it, & let us know!
4) Is it a very recent spill?

We'll pretend it's Latex for now...
* Soak a towel in hot water, & drape it over the affected area.
* Keep towel wet & periodically re-apply/mist hot water for a day.
* Use a 3M scrubby-sponge & ligthly scrub WITH the S/S graining.

Faron

I tried rubbing alcohol nothing came off . its an old spill. the shelves it smeared all over and the doors are spotted....

Heat may be your only friend here now...of the paint-stripping heat-gun variety.

Since it's stainless, try maybe one of the "safe" strippers. Try it first on a lesser-noticed area first.

Since it's an old spill, and therefore baked-on many times over...removal may not be worth the effort!
What brand of grill?

Faron

safer strippers?
its a napolean bbq

would methy hydrate help me determine if its latex or oil based?

Try automotive gasket remover or aircraft stripper; both aerosol cans. And both are for getting stuff off of finished metal.
Casey