Issues with initial height sensing

Wanted to see if anyone has a solution for the problem im having. When doing mutliple cuts, round little metal balls from peircing land on the top of my work. If one of these little balls happens to be under the torch head, it messes up my initial height causing my torch to think its closer to the material then it is…which leads to a failed peirce of the metal. Has anyone found a solution for this? Lake maybe a secondary air stream that will vlow them away before the torch makes contact?