Painted red quarters were used primarily by pinball/video arcades for refunds, free play, machine operation testing . etc.

The "reds" were also often used by store owners/bar owners for other vending machines such as-- cigarette machines, jukeboxes, laundry machines, etc.

What makes this particular coin especially nice is that it's an early clad quarter-- 1966.

The mid-1960s-1970s were the heyday of arcade/vending machines..... by the 1990s they pretty much all disappeared.