Thanks for your quick response!

Your solution is an interesting approach. The reason I'm using a newton field is to accelerate the particles towards the head when it's approaching, like in real world. The idea is to actually see them get sucked in the cleaner head.

As I wrote in the updated post above, all I need is a way to make the particular particle (lol!) stop existing when the collision with the head occurs. I think there must be a kind of command that can be executed in the expression (exactly where I change the particle color to red at the moment) that makes the particle die.

In my first post I somehow missed the chance of adding an attachment with the scene file, so here it is again.

There must be a way =)