Someone said I could use bread to clean the grinder. Is that true?

Yes, bread is a useful choice that can both clean and deodorize the grinder at the same time. Use 1 to 2 slices of bread, pulled into small pieces. Add the pieces slowly, operating the grinder after a few pieces are in place. Tip out the crumbs into the compost bin, then repeat with the next pieces until all of them are used up. This is a good way of cleaning the grinder if you've used it for anything other than coffee, such as nuts or spices, as it'll remove both odors and pieces of the food, making the grinder clean for coffee again.