why pay for a degreaser when we all have a old battery somewhere. empty the old acid on the stains and use your wife's best house broom and scrub for a few strokes and hose it off. now you will have white concrete to bleed on when the wife gets home or you are a M.G.T.O.W. and have no worries. I do like the use a old carpet on a plastic sheet idea a lot. good for the knees when one is on them chasing the run away nuts.