half-metal or weared metal materials

Hello there! Can anyone explain me the metal-rough workflow, or give a link to a magic tutorial, that explains how to make properly half-metallic materials, or how to import them into UE4?
The problem appears every time, when i want to make weared metal (like on screens below), and i see those annoying white flakes on the border between scratced paint and pure metal. And i have this problem especially when i’m using Substance Painter mask with Metal Edge Wear generator (but also when try to make textures in PS).

However, there are lots and tons of models on Sketchfab, using the same metal-rough shader, and without those chunky things on paint-metal borders. I know, that the problem is in places, where metal almost gone, and bright places of albedo channel appear in the final material picture.

It’s not in PBR theory, because i understand the problem and rather interested in workflow. Can anyone tell me, what is the trick, what did i miss?

my ugly screens:

cool screens from sketchfab: