Some versions of the spray paint gear allow you to input a custom Decal ID . By finding a "rainbow" or "spectrum" decal on the Roblox Creator Marketplace, you can effectively "spray" a rainbow pattern onto surfaces.

You can simulate a rainbow by manually overlapping different colors from the RGB spectrum. Using lower opacity settings and overlapping strokes creates a smooth, gradual transition between colors, similar to a rainbow ombre effect.

Occasionally, special Roblox events like "The Hunt" offer unique spray paint items or badges as rewards. Completing these limited-time challenges can sometimes unlock specialized cans or effects without spending Robux.