Hi Larry. I'm not expert by any means, but the empty cartridges I've purchased have had dry filler in them. I'd say if it's wet, it has e-liquid in it. All you have to do is take the filler out and you can direct drip on the atty. If you don't want to direct drip, you can take the filler out, rinse it out well, dry the filler with a paper towel, but it back in the cartridge and add your juice to the filler. You don't have to vape the liquid on the filler.
Good luck.