Room 4 Key

Opens a door in Greystone Estates.

How to obtain

Found in the world

Location	Found at	Conditions
Greystone Estates - Laundry Room	Ghost Woman	You have talked to June Once you have seen the twitching woman on the Greystone Estates rooftop Only once — you have not taken it before

At least one listed source is a one-time pickup; avoid using the last copy until its recipes and collection requirements are complete.
It cannot be sold, so keeping it does not sacrifice any direct sale income; retain it for its listed effect, unlock or collection purpose.
Its stated function is: Opens a door in Greystone Estates. Plan its use around that effect rather than treating it as a generic sale item.