FYI, I found a solution to the same kind of prob as the original poster. A cheap woven rug made of synthetic materials had "etched" it's pattern onto my floors (which were red oak with a satin water-based polyurethane finish. And BTW, I did NOT put the rug down until several years after the floor was finished). Tried rubbing alcohol first, but it seemed to actually sort of "melt" the finish a little, and even though it helped a little, it seemed way too dangerous to use, I mean it seemed like it would just remove the poly finish if I rubbed too hard. So simply I tried LIGHTLY rubbing with "0000" steel wool (WITHOUT using any alcohol or mineral spirits or anything) then lightly buffing by hand, and it worked like a charm! Hope this helps.

My son currently works as a 3rd party engineer for one of the felt rug padding and carpet padding manufacturers Rug Pad USA, Mohawk, Shaw.... and I've actually asked him this same exact issue. I'm a designer down in Savannah GA and our summers are as humid and muggy as they come. I asked him specifically what pads would work to avoid the "Sweating" issue. My clients and I complain about this all the time - the pads get glued to the floor. One of my clients had to replace a portion of their hardwood to fix this issue. He has an engineer background does this for a living, thus most of what he said went over my head....but here's what I gathered... - A 100% felt rug pad is actually recycled polypropylene fibers but it won't ever stain, nor sweat, but the rug has to be large enough not to move. But with smaller rugs, you need to stick with a rubber or latex product to prevent "sweating" and sticking. - Felt and rubber rug pads are made with either synthetic latex (lower cost) or Natural rubber (more expensive), he thought that both should be dry enough that they shouldn't sweat between your floors. So this is what I have been recommending to my clients. I also asked him about the different materials - since I told him one of my clients floors needed to be replaced. Heres what he said "your flooring surface finishes are whats important, not whats underneath them, and to be especially careful with vinyl, acrylic, and laquered finishes. Some PVC padding, not all, can leave an imprint on this type of flooring if they don't get the formula correct, or if they use cheap fillers rather in place of proper materials, or if they haven't been tested on before. Pads that tend stick to floors, melt, sweat, are always made with pvc and essentially all come from low grade suppliers in China." Some food for thought :) - Hope this helps

Yes, I'd get a felt pad. In my case, the pattern of the seagrass rug pushed through the backing and basically created an imprint of the pattern on the hardwood floors. One of the felt pads I bought was from IKEA. http://www.ikea.com/us/en/catalog/products/90132261/ It was by far the least expensive and performs as well as the more expensive (larger) felt pads. Search gardenweb for advice on where to buy felt pads if you don't want IKEA's

So long as it says "Safe for Use With Hardwoods" you will be fine (as in no stains on the finish). High humidity and wool = no problem. Wool is used in damp areas (think Scottish highlands, Northern England, Wales, Norway, etc) as a way to stay warm even when wet! The wool rugs are fine the way they are. If the Spilltech prevents moisture from hitting the wood, I would say it is more likely to ruin your rugs rather than your floor. And remember: they are NOT used as 'grip'. They do not prevent the rugs from moving around. The information given is for LARGE AREA rugs (smallest being 6ft x 9ft) that are so heavy they naturally stay in place. As a "padding" it looks to be quite nice. As a moisture barrier that offers a bit more "time" should a big spill occur - it looks fine. As an "anti-slip" rug pad this fails. As for "safe for hardwood" you should be fine.