I don't remember where I heard this, but I think it was in SING OUT! back in the '60s. I tried it a few times and it certainly did rejuvinate the strings, but you'll never get strings to last forever. After boiling they go dead a lot faster than new strings. Someone, I think it was Jason Fowler, told me that Gordon Lightfoot recomended this method of bringing life back into old strings. He said you have to be sure to take them off the guitar before boiling.