We just had a new front sidewalk poured about 6 weeks ago. It is colored (all the way thru) and stamped. While we were waiting for it to thoroughly dry, before sealing it, some squirrels stained it with some kind of nuts. The stains are a bergundy color on lite brown concrete. We have tried various household cleaners and they have lightened the stains, but they're still there. I thought of acid washing it, but wonder if that'll set the stains and they'll never come out.