who uses them ? good idea or bad ? im talking fuel and oil additives. a friend works for a place that bottles all the slick 50 products. if a skid gets damadged of the shrink wrap lets the load slide off it gets picked up and thrown out and the employees have the option to take it home for free. needless to say i ended up with about 6 cases of fuel injector & fuel system cleaned and 4 cases of engine treatment. who all believes in this stuff ? i'll probably try it as the price was right but anyone know of a down side.