DCDow Corning High Vacuum Grease Lubricant 2oz (57g)

does it wash off with soap and hot water ? or how do you remove it once used ?

Will this work to prevent vacuum leaks in an automobile engine ?

Is this grease plastic safe? will not deteriorate plastic?

Can you use this on fittings for residential hvac systems? i.e. gauge/unit connecting hoses and micron gauge?