I have my Xiaomi Redmi 4X since 2017 and I've been regularly cleaning it (thoroughly; front, back, sides, everything) for like 2-3 times a day with 70% alcohol (isopropyl) and I have 0 problems whatsoever. Zip. That's like I've been cleaning it for over at least 3000 times. So I can attest that there's no problem whatsoever. Also glass is glass and glass doesn't corrode just because of some alcohol that evaporates in like a 2-3 secs. YMMV but for me I haven't got any problem whatsoever from doing it for years. In case you're wondering, the way I did it is by using a clean (dry) facial tissue (a toilet paper or any sterile unused tissue should be ok too). Soak it in the alcohol until it's damp (but not too much), and then gently wipe the phone (in a circular motion). Wipe excess alcohol with the dry part of the tissue. And we're done. Seriously guys, smartphone's screen is like the 2nd grossest thing beside a toilet, so you should clean it regularly, at least once a day! No excuses. Why would someone not...