I’ve always wanted to deface some fash flag pins with acid or oxidizers. I mean, the only real reason you shouldn’t is because it’s dangerous as hell and it’s absolutely not worth getting hurt over trying to do it. Also, chemicals are expensive and ordering even extremely commonly used industrial chemicals like hydrochloric or sulfuric acids can you can get out on a drug manufacturing or terrorism watch list in the US and elsewhere (it’s actually a really big problem for independent hobby chemists because the government thinks anyone ordering chemicals that isn’t a major company or university is suspicious).