If you are using the "touch and flow" applicator, don't leave Tenax in it for too long. Tenax is not a "pure solvent", as opposed to MEK(Methyl Ethyl Ketone), or even Testors liquid, and if it dries in the applicator, it will require cleaning before the applicator can be used again (
or replaced). For styrene, I prefer MEK, and apply it with a very fine brush ( 000) for small details, and a heavier brush for the larger pieces. Ventilate!, Ventilate, Ventilate, and minimize skin contact. MEK works well, but is toxic.