For those unfamiliar new to the game from Alexis's blog

The Destruction Of The Gem.Before getting started it is crucial to be clear that removing gems from a piece of D2R Items gear cannot return them back to the player. While those who adhere to the method as described below will leave with a clear item that will be able to receive new gems, they won't be able to transfer the gems that were previously used to another item.

That means players will have to keep acquiring gems as they progress through the game, since they won't be able to reuse gems that were already put into sockets. Find the most suitable places to harvest and ensure you have an additional gem ready to go prior to removing the old one.

How to Remove Gems within Diablo 2: Resurrected.The way to eliminate Gems from sockets is to use the Horadric Cube, an item that is available from the bottom floor of the Halls of the Dead in Diablo 2's second Act II. It's tied to various quests and can be utilized in the beginning to come up with a myriad of recipes and mixing gems.

For those unfamiliar new to the game, the Horadric Cube has the ability to transform any combination of items into something else which is how gamers clean their gear pieces that are socketed. Specifically, fans must use the item socketed as well as it's a Hel rune as well as buy D2R ladder items a Scroll of Town Portal into the Cube. Then, press "Transmute."