how to switch salvage title to clear title?

There are ways.....some of them completely legal! First of all, there are different rules and procedures determined by the individual states so this may not apply to areas outside California. The easiest (though maybe not the most desireable) is to let the registration lapse for 10 years and the VIN is purged from the DMV database. Then file a lien on the car and get it retitled that way. Clean title as far as the DMV is concerned but if you run a CarFax or similar, it may still come back as previous salvage which might be a drag for insurance or auto loan purposes. The other way is to register the car in a state that doesn't have salvage titles. That list is getting smaller but I think there a few left. There again, it will probably show up as salvage on a CarFax. Other than resale value, why bother? You know what you have....