Wildcat evo cleaning fouling build up

[Tikkat3xl]

Hi all, what is the best way to clean this off my wildcat evo mod (Attached photos)
I’ve tried hot water and fairy, solvent and bronze brush.
Thanks

 

[Miki]

You can't (short of filing it off, which I don't recommend)... it won't be a problem.

 

[Rusty Gate]

Looks clean, the silver pitting is from gas cutting/hot blast

 

[reloader54]

 

[Edinburgh Rifles]

The stop cleaning them..
They are noisier when clean and the carbon layer is protecting the metal as much as it can

 

[swaro79]

Having a evo mod aswell that is gas cutting on the stainless nipple! caused by fast rounds.I had the same problem with the purple diffuser mine was actually worse.what happens is it will start closing up the bore or start moving inwards if you leave it long enough!even first hole inside the diffuser starts to open up with gas cutting and starts to leave alloy pieces in path of round and then it will start affecting the accuracy.what I did was got a dremmel with a circler fine grinder bit and smoothed it out and it was bang on for another good few boxes of ammo.but it will get to a point where you will have to buy another diffuser for it.as for cleaning ive never done but wild cat mods do recommend exactly what you've done soap and water hope that helps.