I guess that you need clear printed part without no treat. We have trial several type of trans filament, such as natural pla, trans abs, petg, pc, pmma and natural tpu. To be honest, All of them are muddy ins surface. Petg is the best one we have used. PC and PMMA is hard for printing, due to high temperature.
Below are our post about this:
https://www.ecoreprap.com/best-clear...te-guide-2018/