To begin with, you should clean your bed mattress every 6 months or so. The other things you can follow in order to keep your mattress clean and maintained are as follows:
1. Vacuum clean once every month.
2. Do not jump on or bend your mattress.
3. Every one to two weeks, wash your sheets.
4. Protect your mattress from stains by using a mattress protector.
5. Pull the covers back and let your mattress air out for a bit each day to let it breathe.
After any spills, clean your mattress as soon as you can with some warm, soapy water and a rag.