get some SPARTAN paint stripper put the panals over some cardboard then get some 36grit sand paper and then just scratch the s#$t out of the paint so there are some scratches that go back to bare metal then get some 2inch masking tape and go right around the edges with it and come in from the sides about 20mm so that there will be a 20mm strip of paint right around the edges that dont get paint stripper on it, this is so that the stripper does not go to the underside or get into the sealer althe otherside, then after you have masked the edges get the paint stripper and pour it all over it (also make sure u are wearing a dust mask or just a papermask and saftey goggles and gloves) then get an old brush and spread the stripper all over the panal then if you have it get some big sheets of thin plastic or glad wrap or what ever you can get your hands on to cover the panal this just helps stop most of the fumes from going everywere, then give it about half an hour or so or more then when you can see that most of the paint has bubbled then carfuly take all of the plastic off and then get a big bladed scrapper or something and then scrape asmuch of the stripper and paint of as you can, once you have done that get some thinners any thinners will do and then squirt it all over and wipe it off with a clean rag (do this as many times as you want) after this then you can take the tape off the edges and now get a sander with some 80 grit on it and go over the whole lot untill the full serface is bare metal right to the edge and then if you are going to fix any dents in the panals i would recomend to do it now, after you have sanded it all with 80 and fixed any dents then go to some 120 grit and go over it all and repeat the prosses with 240 and 380 and this is as much as i can help you with as i am not a spray painter so i hope this helps, or the other option is just sand the lot but this makes a bit more of a mess but yea this is wat i would do