They're both utterly and completely useless. Why do you think you need to clean your VCR? Panasonic and most other brands, AFAIK, have had a built-in self-cleaning wand for years. It usually activates whenever you eject the tape.
Panasonic probably recommends the dry type because it has the least potential to damage the machine, not because they work.
If you need to clean the VCR heads, do so properly, by removing the cover and using foam-covered cotton swabs and 99% pure isopropyl alcohol.
EDIT: If you don't feel comfortable working inside your machine, do as RossMan suggested and bring it in to a TV/Electronics repair shop, and tell them to clean it.