Social media is awash with life hacks and cleaning tips , from tricks to keep your clothes smelling fresh for longer to cooking hacks that promise the perfect roast potato. However, just because a hack works doesn't mean it's advisable to follow it. A bathroom expert has sounded the alarm over a popular TikTok trick that could lead to a mouldy bathroom disaster. The 25p trick, which involves smearing a bar of soap or some shaving foam on your bathroom mirror to prevent condensation during a