Remove gpg key that I added using apt-key add

  1. First you need to find the key id of the key you added. Do this by the command:
sudo apt-key list
  1. It will list all the keys that you have, with each entry looking like this:
pub   4096R/130D1D45 2019-07-15 [expires: 2020-10-07]
uid                  Spotify Public Repository Signing Key <tux@spotify.com>

Once you have figured out which key to remove, use the command sudo apt-key del <keyid> where <keyid> is replaced with the actual keyid of the key you want to remove from your keyring.

sudo apt-key del 130D1D45
apt-key list | grep spotify

source: https://askubuntu.com/questions/107177/how-can-i-remove-gpg-key-that-i-added-using-apt-key-add