I am getting back into the hobby after being out for about 5 yr. I picked up a used Waterbox 20 today. It was taken down after a tank crash back in August. I started cleaning it up when I got home, I cleaned it with vinegar and a razor and am still not able to remove these water spots, while it did clean up, there are these marks that look like someone wiped it with a wet towel and left it. I can’t get it off and it’s driving me crazy. What can I do? Muriatic acid and a sponge and rinse? I haven’t added water yet except outside to clean it. Maybe these won’t be as noticeable when it’s filled up. I have scrubbed and scraped to no avail.