Has anyone buy any of these wrist pad cover protectors? I want to protect my mbp from stains. But I do not want to make any harm to my mbp aluminum case while I trying to keep it always clean. I am afraid of 'glue' trails over time, by using such 'protection' products, even though in the product description they claim that they 'will not leave a sticky residue when removed'. Does anybody tried any of these? I want to buy a quality product, from ebay-amazon etc, and not a bad one.