There are a few ways to remove an AUG flash hider, but the simplest and most effective method is to use a flashlight hider removal tool. These tools are designed specifically for removing flash hiders from AUGs, and they make the process quick and easy.
To remove the flash hider, first, discern which type of retention system is being used. There are two basic types: those that use set screws and those that use a bayonet mount. If the latter, you will need to remove the bayonet cap before proceeding. Once that is done, align the tool so that its jaws line up with the six slots in the base of the flash hider ( three o’clock; nine o’clock). Gently but firmly squeeze the tool’s handles together until the flash hider pops off. If your flash hider is retained by set screws, use the appropriate size Allen wrench to remove them before proceeding as above.
With the flash hider off, you can now inspect the muzzle threads for damage. Chances are good that they’re in good condition, but it’s always best to err on the side of caution. If you see any damage, smooth it out with a tap before reattaching the flash hider.