A regularly used diffuser will inevitably stop working if it is not cleaned on a regular basis. Therefore you may cause it to run out of use and you may need to buy a new one. To avoid such unwanted problems, the key tip is to clean your diffuser with an effective cleaning material. Most of experts would recommend using vinegar.
To clean your diffuser you will need a fair amount of distilled white vinegar and cotton swabs. Submerge the cotton swab in vinegar and clean the oil buildup accumulated inside of the diffuser.
Source: essentialoilsqueen.com