I'm using tow truck and removal team but they can't do it always. I found in native trainer ''clear area'' command. It can clear all objects, vehicles and peds from the area (you can adjust range). This is by far the best thing I've found. When you have 5 or 6 cop cars in one pile, even if the removal / tow truck works, you'd have to call them multiple times in a row, it's time consuming. So I guess I kinda solved my own problem here :D