Sign in to your tax return, and click on State in the left-hand side of the page. Go back through the STATE interview, and when you get to the question about the Home Heating credit, answer NO.
If you still have a problem removing the credit, find and delete the related tax form. For Michigan, it is MI-1040CR7. You can find the list of forms by click on Tax Tools on the left side menu. Then click 'Tools' and then 'Delete a Form'.
