Enamel paint is a good choice for many surfaces, especially outdoor areas where inclement weather is an issue. This paint is widely used because it is very durable, even when exposed to harsh conditions. Enamel that is coated with a glossy finish is even more durable, and a high-gloss coat is simple to clean. However, if you prefer the look of matt enamel paint, and you don't need the benefits of an easily cleanable gloss, you can remove existing gloss from a painted enamel surface with just a little work.
Touch the painted surface to see if it is tacky. Once gloss is mixed into wet enamel paint, it can be removed only after it dries; there is no way to directly separate liquid gloss from the paint mixture. For a freshly painted enamel surface, the paint should cure at least 24 hours before you remove a glossy coating. If the paint is even slightly tacky, don't risk removing the gloss until it fully dries.
Sand the enamel painted surface with 220-grit sandpaper. Sandpaper removes the topmost layer of gloss for a rougher, matt finish.
Wipe off excess sandpaper dust with a damp rag.
Put on rubber gloves.
Apply liquid deglosser to the surface using a rag. Liquid deglossers penetrate deeper layers of polyurethane gloss for more complete removal. Let the deglosser sit for about five minutes. Don't let it sit for too long, as it can eventually take some pigment out of the enamel paint. Deglossers rarely remove entire layers of paint, but they can discolour the painted finish if you let the liquid sit for too long. Generally speaking, liquid deglosser won't damage the enamel paint if it is removed within five minutes, but consult the label to make sure.
Wipe off the liquid deglosser using a clean rag. Some of the glossy finish should wipe off along with the liquid, leaving a matt enamel finish behind.