Prinz Uhu Stamp Lifter / Stamp Remover

Does anyone have a more experience with this product? What is the best way to use it - to drop the fluid on the stamp, and wait an hour or so that it become completely dry... and remove it that way... or it is better to try to remove it after just a couple of minutes, when the stamp is still wet? I have tried both solutions, and still didn't find the optimum one... Does anyone else have some better results?

I have tried a product called Stamp Lift Fluid, and it never seems to have good results. The gum on mint stamps always looks strange after use.