Google today announced that it will ban from its Chrome Web Store any and all browser extensions that mine crypto.

Mining cryptocurrencies in the browser isn’t the most efficient way for individuals to get rich, but if you are a developer and you get thousands of machines to mine for you, that equation changes in your favor. For the longest time, Google’s Chrome Web Store allowed for single-purpose mining extensions. That is, developers could publish extensions in the store that clearly stated their purpose and that had no other purpose than to mine.

As it turns out, 90 percent of extensions that mine crypto don’t comply with those rules. The lure of cheap Monero is simply too great for some developers, so they try to smuggle their mining scripts into what look like legitimate extensions. Some of those get detected and removed outright and some actually make it into the store and have to be removed. Google is obviously not happy with that, as it’s not a great user experience. Those extensions tend to use a good amount of processing power, after all.

So starting today, Google won’t allow into the Chrome Web Store any extension that mines cryptocurrencies, and starting in late June, all of the existing extensions will be removed. It’s worth noting that Google will still allow for blockchain-related extensions that don’t mine.

“The extensions platform provides powerful capabilities that have enabled our developer community to build a vibrant catalog of extensions that help users get the most out of Chrome,” writes James Wagner, Google’s product manager for its extensions platform. “Unfortunately, these same capabilities have attracted malicious software developers who attempt to abuse the platform at the expense of users. This policy is another step forward in ensuring that Chrome users can enjoy the benefits of extensions without exposing themselves to hidden risks.”