Destroy a sprite

How does one destroy a sprite/mark it for garbage collection?

I have a Key sprite, when the character picks it up it should disappear. It won't be needed again.

I think by calling its remove() method?

And if you have a reference to it anywhere, set that to nil

[spriteVariable]:remove() will take it out of the rendering / updating per frame.
(Inside Playdate)

But then to remove it from memory, as Gamma mentioned set it's reference / variable to nil