scraper for the shake out bag that used to go in that slot..
Nope--it's a coin slot.
Every Kirby since the D-50 had a sani-pocket, but they didn't start with the coin slot until the Clasics.
In a demo the saleperson would say "And if you save the coins you pick up while vacuuming, the Kirby will pay for itself." Then he would drop in a quarter and say "See, you're saving already." Smile, chuckle, and pulls out the contract.