Yes Miguel, good pictures for a $100 camera and indeed the macro function seems to work quite well.
I don't think it is a problem with your images because the weave of you matt is pretty tight, but it reminded me to suggest that when choosing a background, try to find one that is solid in color with a fairly nuetral texture so that it doesn't distract from the object you are photographing.
Jens, shiny, reflective surfaces are a bitch, even for professional shooters. I am unaware of this spray silcone wax you speak of, but it sounds like it might be difficult to remove latter. One thing you can try is to get a large white card and cut a hole in it that is just big enough for your lens. You will still get a little bit of reflection of the lens, but at least you won't be making self portraits.
You can also try approach the subject from different angles to try to minimize the reflection.