The idea behind at least the Combak dots (and the Marigo ones too, I think) was that they would take vibrations from whatever they were attached to (I had some on my speakers, even some on circuit boards inside my old Krell SBP 64x) and re-tune them to a different frequency, so they didn't adversely affect the music. I opened one of them up, and inside there's a little piece, apparently metalic, that looks like a form of a tuning fork, so I think that the theory really is being implemented. On my Duntech Princesses you could clearly hear a difference for the better in terms of midrange clarity and slightly better-defined bass, but on other equipment, such as the DAC, the effect seemed negligible to me. I'm sure there are some who heard a change for the worse as well in their experience--remember, just because the sound changes doesn't always mean it's for the better.
If the dots were expensive, they are likely the Combak dots, which were pricier than the Marigos. It will be very hard to remove them (you'd need dental floss), so I'd just leave them in there, if you like the sound.