Here's a nozzle brush that you can friction mount to your Ender 3. I found and modified a Klipper script here: https://github.com/VoronDesign/VoronUsers/blob/master/abandoned_mods/printer_mods/edwardyeeks/Decontaminator_Purge_Bucket_%26_Nozzle_Scrubber/Macros/nozzle_scrub.cfg

I designed this to fit these brushes on Amazon: https://a.co/d/1DBlw8a

Printed with supports oriented with the longest flat edge on the build plate but I may not have needed them.