The laundry won't pay their protection money so Toni wants you to MAKE them pay it.
Dirty Sheets
Drive to 8 Balls garage where you'll find some Grenades. Pick them up, then get back in your vehicle. Drive around the map following the Triad Fish Vans on the radar. When you get close, throw a grenade at them to blow them up. You can alternatively smash into their vehicle with yours, drive-by their trucks or use any other weapons you would like. Once all three trucks have been blown up you'll pass the mission. Make sure you stay out of the way of the explosions though, or you'll be blown to bits too.
Mission Passed!
$20000
Additional Notes
Just keep your distance and you should be able to take out all three trucks without taking any damage at all. Drive-by's work best if you buy some Uzi ammo from Ammu-Nation.