[Venom]

Hello guys,
problem cleaning stainless steel mesh. Black residue cause a decrease in filter life thus leading to early cleaning. Kindly respond with appropriate methods. As of now they are being cleaned.
via hydrolysis at 350 degree Celsius
alkali cleaning with a 14% NaOH soln and oakite 33
Demin Water at 99 degree Celsius

Thinking of adding an acid wash or phenol bath. Ideas are welcome. Professional opinion is appreciated. The substance being filtered is polyethylene terephthalate at nearly 290 degree Celsius

[Arkcon]

I wouldn't wash a stainless steel mesh with acid, although it depends on what acid you choose.  What is the black residue?  Is it charred organic?  You're not going to help that with a mild acid, and strong acid will present disposal problems.  How is your alkali wash working, is it good enough?