ordinary urethane absorbs oil and an incredibly lower rat ethan any resin. Wipe th eball off during bowling so it skids less. Baking for an hour is not good; 10-15 minutes at a time MAXIMUM, and then for resin, NOT urethane; washing in hot water and dishwasher soap is much safer for resin only.
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"Just because you can do something does not mean you should do it."