DIAGNOSIS: Dust builds up on the internal vertical blades, reducing airflow and efficiency. The fan isn't designed for super easy user disassembly, so you have to work within its constraints.
FIX: Unplug the fan. The main method is using the brush attachment on your vacuum cleaner. Many Dreo tower fans have a rear grille that's more open. Gently insert the vacuum brush nozzle into the rear openings and run it along the length of the fan to pull dust off the blades. You can also use a can of compressed air: insert the straw through the front or rear grille and give short bursts to blow dust off. Rotate the fan to access all sides. For sticky grime, a long, thin microfiber cloth wrapped around a chopstick or butter knife can work, but be very gentle.
IF THAT DIDN'T WORK: If the dust is caked on and you need a deeper clean, some owners have carefully removed the front plastic cover by finding and undoing the hidden plastic clips. However, this is not recommended by Dreo and can easily break the clips, leaving your fan rattling.
HEADS UP: Never run water into the fan or submerge any part of it. Don't try to spin the blades manually with force if they're stuck—you can damage the motor. Regular vacuuming every few weeks is way easier than a deep clean later.