It may be more trouble than it's worth. If you scrape and sand the gummy clear coat off, you will probably find that the base color has been damaged too. And if that's the case, since you don't know what it was painted with originally, you don't know what will be compatible with it. So the base color will need to come off too. What will probably make more sense is to remove the covering entirely and start over with Sig Koverall or Stits fabric and then paint using a known fuel proof paint. Butyrate dope is the traditional choice, and it's light and looks good. Nelson's or Systems 3 water based polyurethane with the crosslinker added is a good option too, especially since it doesn't smell and the reducer for it comes from your kitchen faucet. And Klass Kote epoxy paint has served the hobby well for years as the most durable option.