Warren Buffett has doubled down on his distaste for cryptocurrency and it does not seem like his stance will be changing anytime soon. The Berkshire Hathaway CEO had harsh words Monday for crypto in a CNBC interview.

“Cryptocurrencies basically have no value and they don’t produce anything,” Buffett said. “You can’t do anything with it except sell it to somebody else, but then that person’s got the problem… In terms of value: zero.”

Buffett is no stranger to criticizing cryptocurrency and bitcoin, in particular. In 2018, he called the currency “rat poison squared.” At various points in the past, he has also derisively called bitcoin a “mirage” and “tulips.”

“I don’t have any cryptocurrency and I never will,” Buffett went on to say.

In 2019, Justin Sun, founder of the TRON cryptocurrency, paid $4.57 million at a charity event to win a meal with Buffett where he endeavored to change the billionaire’s mind on digital currency. Despite Sun and the company’s best effort, Buffett remains unconvinced.

“When Justin and four friends came, they behaved perfectly and we had a very friendly 3-and-a-half-hour dinner and the whole thing was a very friendly exchange of ideas,” Buffett said. He did give Sun kudos for his generous donation, which went to Glide, a homeless charity in San Francisco.

Buffett further criticized the tendency for bitcoin to be used for illicit purposes. In particular, he noted that the cryptocurrency had notably been used to illegally launder large amounts of money. Jokingly, he suggested the crypto’s biggest impact on the world economy might be the decline in sales for suitcases used by criminals to hide cash.

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Warren Buffett speaks at a fundraiser for Democratic presidential hopeful Hillary Clinton 26 June 2007 in New York. STAN HONDA/AFP/Getty Images