Edible Ginger-Infused Cooking Oil
Leave skin on the ginger and slice paper-thin with a mandoline slicer if possible.
The only way to end up with the best product possible in my opinion is to remove as much moisture as possible from the root. I have had different herb, root extractions or macerations mold over due to not getting all the moisture out that I should have.
After straining the ginger pieces, you can grind them finely to use in a poultice or paste, or compost them.