Sep 11, Don't toss out your used coffee grounds just yet! I'm sharing 20 brilliant ways to put those grounds to good use - inside and outside of your. Dec 28, With care, used coffee grounds can be added to the vegetable garden soil How much caffeine actually remains in used coffee grounds is. From use in the garden, to around the house, there are many things that can be done to recycle or reuse your old coffee grounds. Ideas for Used Coffee Grounds.