Descaling Questions for Mobile Undercoating Business

I run a mobile oil undercoating business, i’m still in the beginning stages of it. I apply NHOU Black, but I was looking at adding a descaling service to it as well, to remove loose or flaking rust before i apply. NHOU is designed to soak in and knock off rust over time, but not that loose stuff. What would be an efficient way of doing so, with simple and effective tools? I use a wire brush, but i don’t feel the confidence in it. Something a step up from wire would be great imo.