This user script removes ignored questions from the question list. You can get the script here on github. Requires you have a userscript plugin like Tampermonkey.
When you use this script, it adds a little checkbox to the list of questions:
Check it and the ignored questions in your list go away
The state of the checkbox is remembered across page loads, so you can keep these questions permanently hidden. Uncheck the box to show ignored questions again.
Please note, the script that applies the ignored style to the questions doesn't run immediately on load, and can take some time to complete. I haven't spent the time tracking down the function to figure out if I can hook into it somehow, so I am simply setting a timeout to kind-of wait until I'm reasonably sure the script is completed. You can adjust this timeout to suit your needs.