I like that sign, but wanted the option to have the "Clean/Dirty" in green/red.
First, the CLEAN letters are printed. Then the DIRTY letters without removing the previous ones from the print bed. Finally print the thing over the letters. Important: Z-Hop must be set higher than the letter height. The letters have a height of 2 layers, in my case 0.25mm + 0.2mm = 0.45mm. So I set Z-Hop to 0.5mm.
The author remixed this model.