I’m asking this question on behalf of my mother who recently ran over a can of white spraypaint that fell off a truck. She went to the car wash to try to get it off, but they only succeeded in removing some. What products or methods to you recommend to get the rest off without destroying the paint job? Thanks in advance, from me and my mom 
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Depends on how much paint we’re talking about. If it’s just a few dots then you can pick up some rubbing/polishing compound from your local car parts store and that should take it right off. Should you doubt your skills with this stuff (I routinely ruin parts of my car’s finish with it, but I’ve seen regular schmucks just like me turn crummy paint into a marvelous finish with it) you can check with an auto detailer–many will take care of small scratches using it–no reason they can’t remove some spots from a spray can.
Now if Mom’s car really got blasted I’m not your guy. But another alternative is to make your insurance company pony up. If the paint can fell from a vehicle ahead of her the claim could very well be considered a COMPREHENSIVE loss, the area would be fixed and she’d pay her deductible. As a general rule, comprehensive losses don’t incur a premium surcharge because they’re not your fault. Depends on what state you live in, who the insurer is, etc. If you want to go this route, call your claims office (not your agent) and ask 'em a “what if” question.
Is the paint oil or latex?
When I was much younger I had to remove grafiti from the walls of the place I worked. I would use some stuff for cleaning grease from car engines. It is called Gunk and if it is still being made, it can probably be found at the automotive department of K-Mart.
HOWEVER, I am not convinced that it will take the spray paint off and leave the car paint. I would be VERY cautious.
HTH
The exact same thing happened to me. I ran over some punk’s graffiti spray paint can in the street, and got black paint on my white Honda. Mr. Pug asked an independent contractor/auto detailer if he could remove it, and he did, but we were given a hefty charge for it. He wouldn’t tell us his method, but it involved combining the application of some sort of solvent with heat from a blow dryer. When he was done, you couldn’t tell that the paint had been there.