If you are using darknet/ dark web marketplaces you should use an anonymous bitcoin wallet to mix or launder/ clean your bitcoins.

The best way to have anonymous bitcoins and leave no traces on darknet markets is by using a completely anonymous bitcoin wallet with coin mixing capabilitys.

One of the best anonymous bitcoin wallets is OnionWallet, one of the oldest and most secure and trustworthy bitcoin wallets in Tor.

If you have the Tor Browser installed you can access OnionWallet on http://ow24et3tetp6tvmk.onion/  or you can also access it on the clearnet using this link: http://ow24et3tetp6tvmk.onion.to/