I accidentally uploaded an empty spritesheet instead of the cartridge for a quick test thing, as 20297. Is there a way to delete it so it doesn't gum up splore and stuff?

i just did the exact same thing and came here to ask the exact same question

high five!

I don't know if you can actually delete a cart, but you can just remove the cart tag from your post.

I didn't even make a post, it still appears in Splore.

... or, it did. It doesn't now. Weird.