Hi Ramesh Gupta Uppala

1. You can try an electropolishing to remove those particles, is a non contact method and if the particles are on the surface of your metal they act as a peak and that promotes a preferential dissolution of the material and the nivelation of the surface.

2. You can try the same for this but I don't have experience with that.

Best luck, Regards.

You could improve this situation by ultrasonic cleaning.

Laser drilling or laser cutting are excellent technologies, but in both cases the process produce many types of deffects (spatter, HAZ zone, recast layer, burr, and so on). The magnitude of this type of deffects may be controlled by the laser parameters (for example, spot position, power percentage, laser speed).