Most of the repurposed tins I have seen were spray painted. I was worried about the paint chipping easily, though any paint on tin has a tendency to do this. Besides, I have a quart of black chalkboard paint in my paint stash. I used a foam brush and after several coats of paint I was satisfied with the coverage. Applying Annie Sloan black wax next and letting that cure for a day I was ready to add the vinyl lettering. I used my cutting machine to cut out the lettering, but any method of decoration at this point is possible.
Second Chance To Dream