It is important to regularly clean your fan to ensure trouble free operation. 

Ensure that the fan is switched off from the supply mains before removing any guards.

Unplug the fan from the mains supply before cleaning.

Use a damp cloth (not wet) to wipe the exterior of the fan to remove dust and dirt.

Use a vacuum cleaner to remove dust and fluff from around the grills (where applicable.)

Ensure the fan is dry before plugging back into the mains supply.

Do not attempt to dismantle the fan. There are no user serviceable parts.