OK just to complete this thread and as a guide to others, I successfully washed RJDev's topper. I threw it in a front-loader washing machine using the Delicate cycle (cold water; lowest spin speed) and a small amount of Tide. The topper was pretty wet when the cycle finished. I laid it out on some towels on the floor, put towels on top and gently blotted as much water as I could without applying too much pressure to the topper. I then let it dry on a clothes drying rack for 24 hours with the art facing up. At that point, the top surface seemed dry, but there were still some places where the rubber was still wet. Mostly those were the spots where the topper was in contact with the drying rack. I let it dry for another 24 hours and it "seemed" dry, but where the rubber contacted the drying rack, there were corresponding depressions (yes they were depressions not raised areas) on the art side and upon closer inspection it turned our the rubber was still damp underneath these spots. I then laid the topper on my table art side down so that the rubber side could completely dry, which it did after another 24 hours and, viola, the depressions on the art side disappeared. All of the stains and discolorations disappeared, but there were one or two spots where a tiny bit of caked on dirt remained (although honestly most folks wouldn't notice), so I would recommend pre-treating any stains or caked on food with Shout or another spray a few minutes before throwing in the washer. There seemed to be just the slightest amount of shrinkage in length (maybe 1/16 - 1/8 inch) but no shrinkage in width. This may simply be due to a contraction of the rubber after wetting and drying back to its original length. Those who have these toppers and tuck any part of it under the rail know that you can actually stretch the topper a bit as it is very pliable. Anyhow, no one is going to notice this almost impreceptable shrinkage (except for us OCDish types). Bottom line: Yes you can wash RJDev's toppers in the washing machine.