I do not like to leave the clippings but some people find that helpful. I put my clippings in my compost pile. If you have any weeds, you would need to do that anyway. What will accelerate the deteriation of a tree stump . Hannie, Norwich, CT Anaerobic reactions will help.
Chemicals are available to inject into the stump.
Ammate salt crystals are sometimes available in feed or garden shops. Any salt or acid will speed the rotting process. Drilll holes in the stump and add the salt or acid. Be careful, when handling acids. Be sure to use rubber gloves.