While I typically send my own diapers and wipes when my littles go to Grandma's house, it's always nice for grandparents to have a back up stockpile, so I send boxes of diapers and wipes to keep over there as well.
Currently I have a big boxof ancient clothes and holey cotton diapers that need to be recycled, but so far I've been unsuccessful at figuring out where to send them.