Detergent in Stray

In the Slums, turn around with your back to the Keeper and go forward to the first houses (down a couple of steps). On the house to the right of the passage to the bar, there are air conditioners at the end. Jump up on them to find a robot throwing cans of paint. Meow next to him to make him drop the can.

You'll see the robot from the laundry room below come out to clean up the paint. Go downstairs, enter the laundry room and look for a plastic can of detergent on the table on the left.