The following was is taken directly from a published insert in Bowling This Month, authored by Ebonite ball designer Ronald Hickland.
"Tests have confirmed that hear can distort, shrink, crack and reduce performance on a coverstock...During the heating process, the coverstock expands and is strained as plasticizer is expelled. This can cause cracking of the coverstock. When the heat is removed, the coverstock begins to shrink at a higher rate than the expansion, causing the ball to be smaller than the original size. This increases stress and makes the coverstock brittle. These reasons are evidence enough for Ebonite to discourage the use of heat to restore perfomance to a bowling ball."
This is not the first company to discourage the use of heat to restore bowling balls but people continue to do it. What do you think? Will this change how you feel about the use of heat to restore your equipment?