There are different types and sizes of filters depending on the type of CPAP unit you have and which manufacturer produced your machine. Basically there are disposable filters and non-disposable filters, sometimes referred to as pollen filters.
Disposable filters are to be replaced on a regular basis. This means, when your filter appears dirty, discolored, or has collected lint, it is time to replace. You should remove the old filter, throw it in the garbage, and put a new, clean filter in your CPAP machine. How often you need to replace your disposable CPAP filter will many times depend on your home environment. If you have pets that shed or smokers in the home, you may find that you need to replace your filter as often as every two (2) weeks. If you do not have pets and/or smokers in your home environment, you may only need to replace your CPAP filter every month or even every other month. The outside environment may also play a role in the frequency of CPAP filter replacement.
Non-disposable filters, also known as pollen filters for your CPAP machine can be washed. Once a week, it is important to remove your pollen filter from your CPAP machine and wash it in warm soapy water. Make sure to rinse your filter out good to remove any soap residue. Once your CPAP filter is washed and rinsed well, you should set it to the side to air dry completely before putting it back into your CPAP machine. It is always a good idea to have an extra pollen filter on hand to use while your other one is drying out.
You should refer to your user guide or booklet that came with your CPAP machine to guide you through the process of changing your CPAP filter.