League of Legends developer Riot Games has announced that it’s deactivating all previously issued skin codes in order to minimize third-party sites where players have been scammed.

League of Legends is a free-to-play game, and one of the way Riot monetizes it is by selling skins, which customize the color and appearance of the playable heroes.

The third-party sites in question promise players limited edition skins, but in reality the codes they’re selling are acquired illegitimately and exploit players.

“They charge excessive prices (we found one skin for over $1,000!) and sometimes take payment and never provide the content,” Riot said in a post to the game’s official forums. “You can’t predict the outcome, and no purchase is ever guaranteed regardless of what the seller says. To make matters worse these services typically use bots. Bots are lame to play with and chew up additional server bandwidth, negatively impacting everyone.“

In addition to deactivating skin codes, Riot said it’s recommending to multiple payment processors to not process fraudulent payments from these sites.

If you have a legitimate skin code, you have until July 23 to send a request to Player Support along with proof of ownership and Riot will redeem the code for you. Riot will not retroactively remove content redeemed prior to its announcement, but after that deadline it will no longer redeem codes for any reason.

You can find more information on the issue on Riot’s code cards FAQ.