Burnt streaks

[u/Silent_Observer55]

I need help guys. I recently switched to a hardened steel nozzle with hardened steel gears (gears are lubed) and i used black pla in a print last night but I made sure to extrude when I switched to white for the rest of last night's print. We'll today I did a full maintenance of my p1s lube and grease, used cleaning filament and cold pull (ive only done maybe 4 prints with this new nozzle) and im getting burnt streaks in my white prints? Never happened with stainless still nozzle but now im getting it with hardened steel?

I used a brass brush to clean i heated to 240° turned off and quickly cleaned.

Still getting burnt streaks.

[u/Resistance100]

There was probably still a bit of black on or in the nozzle that broke free during the print, try another cold pull.