Found an old Swiss key wind watch. (see only other thread started by me for pictures). Had been laying in a house for decades Key for winding didn't turn, so I assumed it was 100% wound. But didn't move, although it set OK. Started playing with the wheel that goes back and forth (excuse my ignorance, its that the balance spring), and it started running. First only a few seconds at a time, but as I kick started it, ran for longer and longer. Initialy only when held flat, now do-sent matter the position. Has now been running for 20 hours straight. What could that be? Possible that it was just dirt or the like and now freed will run? Any thoughts.