Test 1: pour coffee onto untreated valchromat. Not recommended.
edit: actually it's already dried (after wiping immediately) and it's unnoticeable. Felt like I was brushing off loads of fibers when I was drying (so I probably was) but it's looking and feeling good now. Going to try a few more liquid tests (leaving flask with coffee on bottom for half an hour etc).
Test 1: pour coffee onto untreated valchromat. Not recommended.
edit: actually it's already dried (after wiping immediately) and it's unnoticeable. Felt like I was brushing off loads of fibers when I was drying (so I probably was) but it's looking and feeling good now. Going to try a few more liquid tests (leaving flask with coffee on bottom for half an hour etc).