I thought I would pass along my successful experience removing spray paint from a Sunn 1200S. This subject has been discussed several times on many forums. I suspect that many posts are from well-meaning guys posting their best-guess, but not necessarily based upon actual experience. So here is some real-world results....
The amp cabinet had been spray-painted gold by a previous owner. I did a bit of internet research on this subject and found recommendation for Motsenbocker's Liftoff Spray Paint Graffiti Remover (also referred to as Mostsenbocker's #4). Available from Home Depot in 22 oz. spray bottles or 1 gallon jugs. It's water-based, so not too stinky. And it is recommended for painted vinyl.
This stuff works very well! It takes about 6 applications to get all of the paint off. Here is how I did it.....
Remove the chassis and all of the hardware. Spray the remover on the tolex.....just enough to wet the surface and let it work for a 2-3 minutes. Take a stiff, plastic-bristle scrub brush wrapped with a cotton paint rag (t-shirt material) and begin scrubbing the tolex. The bristles force the cotton rag down into tolex crevices to soak up the dissolved paint. Remember that the goal is to remove the paint, so keep a fresh section of rag on the brush. As soon as it gets soiled or wet, move to a fresh section of rag on the brush. Don't get cheap on the rags or you'll just be moving the dissolved paint around! If you wait too long, the paint will begin to solidify. If this happens, just spray another light coat of the remover.
I found that it's best to do a first application on the entire cabinet to get the first layer off, then do the second application, etc. If you try to completely clean one side of the cabinet, you will inevitably get some spill-over from the next side, spoiling the clean side. You need to be patient, thorough and detailed, but it's worth it. This cleaner will also take the paint off of the hardware.
The cleaned vinyl will be a bit tacky, but it does return to normal in about 30 minutes. You can also wash the vinyl with water to neutralize the cleaner. Re-install the hardware and you are good to go.
I did try this product on painted grill cloth, but it would take a lot more work to remove the paint (possibly soaking the cloth in a bucket of the remover and continually scrubbing it), but I gave up on this after several cycles.
Still, this product works very well on tolex!
Good luck with your restoration!