I have freed up at least 3 saws that the piston stuck and resumed using them. 1 stihl 028 and 1 034 both run on straight gas. The 034 was run by me another 5 to 7 years and sold , the 028 belonged to a freind and hasn't been used a lot yet as it was last spring. If you manage not to sell it try wd40 or another fine lubricant sprayed liberally in the cylinder through the spark plug hole let it settle a while then remove the starter cover and try wiggling the fly wheel back and forth to free it .If your successful mix some fuel 16 to 1 and try it out. It may or may not run ok. On my 034 I ended up using 25 to 1 which I use with most of my saws. I couldn't notice any power loss. The 028 was down some on compression but seemed decent with 16 to 1. Make sure your carb is adjusted properly when switching mixes. If you don't use this info mabe someone else can.