I recall having the same question in Dec./January after we got double recycling in November… what am I going to do with $240 in Rewards?
I finally used the 2019 extra Rewards on Charmin and Bounty in January. Sent cases of it to friend & family. Had no idea they would be a hot item 2 months later.
Buy some ink, sell on ebay.
Another possibility is to buy webcam(s) and resell them. Webcams are hot on eBay at the moment.