Well you can try to work them out with dry-ice and a heatgun. 1st. heat the area alot. Then take the dry-ice and rub it on the dent (deepest to shallowest) you´ll have to do it several times, but it works great on big deep dents. Then sand the area down to metal and use some body filler(bondo). Remove all the gas and be very carefull as the heat gun has exposed heating coils and with the gas fumes... Just use caution.