What is the best way to safely and completely erase all data from old laptops?

I have a couple of old laptops lying around and want to throw them away, but have been cautious to do so because of privacy concerns of data still on the hard drives. What is the best way to wipe them? Or should I take them out and physically destroy them?

They are running windows vista and 10 I think.

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I work at an electronics recycling facility and all laptops that are recycled are completely sanitized and properly disposed of as e-waste. Look around for a local recycling center and check for an R-2 certification, if they have one they will take out any identifiers and do passes on drives via a sanitization device to ensure that the whole thing is completely devoid of all data.

This is the correct answer. Give it a format just to be sure then donate it to a recycling center.