Coaxial cable replacement question

With some specialized tools you can run new ones and abandon the old ones but most people don't have monster rare earth magnet tools to pull tag lines with .. It often takes some experimenting with fish tools to get new cables in. I have cut holes inside cabinets to gain access for some cables. Sometimes you do not have a choice.

I have a monster magnet that looks like a narrow paint roller. A small chain or other small rare earth magnet is inserted into the hole and the paint roller device pulls the small chain or plumb bob device along the inside of the roof/wall/ or under carpet.