Andy grabs some carrot greens and tells aunt bee she should stick them down the garbage disposal. This is actually not a good idea. Disposals aren't designed to handle thick or fibrous substances, especially long ones in bunches.
Aunt Bee and Andy jump on Opie's case about putting perfectly good toast down the garbage disposal. But in the episode "Aunt Bee on TV" she takes cake away from Goober and puts it down the disposal herself.