My favorite bow developed a weak spot in the top limb about mid limb and went from 1/8" positive tiller to about 3/4" with plenty of added string follow.
A few weeks ago I decided to heat the limb on a form to see if I could correct it. My thought was "fix it or destroy it" which ever came first.
I really got the limb hot, not scorched but really hot. This was a snake backed bow so I only heated the belly. When I had the limb as hot as I thought it could stand I wrapped an old tee shirt around the form and limb to retain the heat and let it soak in.
After cooling, first stringing showed a slightly negative tillered top limb, after a thousand shots or so the tiller top limb tiller is about 1/8" positive with minimum string follow.
This time it worked but I have done similar attempted fixes in the past with mixed results.
I did toast the belly of a droopy limb BBO one time and change it from a string following dog of a bow to a straight limb rocket launcher.