Well I personally wouldn't be waiting for it to dry before removing it. It's best if you remove any and all fecal matter/urate/liquid they pass as soon as you see it, and then spot-clean the area. I'm hoping you aren't using any loose substrate in the bottom of his tank, but rather a solid substrate like tiles, non-adhesive shelf liner, carpeting, etc. I won't go into why loose substrates are awful for Dragons, but they are, and the ease of cleaning up bowel movements is part of that...
So instead of waiting for it to dry, which is allowing all the bacterial, parasites, etc. to contaminate the tank, plus it gives your dragon time to run all through it and get it all over himself, just keep a roll of paper towels by his tank, along with a spray bottle of either F10 Reptile Disinfectant or what I use is a spray bottle full of a mix of water and either white vinegar or red wine vinegar. Then just pick/wipe up the entire bowel movement with paper towels, being sure to get all of the fluid, throw the paper towels away, and then spray the entire area on the tank floor with the Disinfectant or the Vinegar/Water solution, let it sit for a minute or two, and then wipe it up very well. That's it. I would not be waiting for it to dry and then using duct tape to pick it up, that's not sanitary at all, as you're not killing or even attempting to remove the bacteria and other microbes that are left on the floor of the tank at all.