[jeffkrol]

Stage 1: Mechanical-Foam Filter Insert
AquaClear® Foam Filter Inserts perform mechanical filtration by
trapping particles and debris as they pass through the insert.
This unique foam, designed for use with AquaClear® Power
Filters, features optimal pore size for efficient mechanical and
biological filtration.

Usually fine to just rinse and return

Stage 2: Chemical-Activated Carbon Filter Insert
AquaClear® Activated Carbon Filter Inserts contain 100%
premium research grade carbon. Premium research grade
carbon provides large amounts of surface area for adsorption of
undesirable impurities. The Activated Carbon Filter Inserts will
remove unwanted odors, discoloration and impurities resulting
in a crystal clear aquarium.

Discard, most feel carbon is a waste at best, detrimental at worst.. Good for getting rid of antibiotics
One option is to replace w/ stage 3.
DO NOT rinse this in tap water if it contains chlorine ect..
I usually rinse it w/ tank water or Seachem Prime treated water..

Stage 3: Biological-BioMax Insert
AquaClear® BioMax Filter Inserts contain BioMax ceramic rings.
The surface of BioMax is made up of a complex pore system that allows bacteria to thrive.
Use of the BioMax Filter Insert will provide optimal living space for beneficial bacteria and
enhance the removal of ammonia and nitrites resulting in a healthy aquarium environment.
NOTE: Regular replacement of AquaClear® Filter Inserts is essential for optimum filter
performance.

Replace w/ poly fill or top off stage 2 (increase size of stage 2) and any fine filter media.
Others have mentioned other substitutes though top should have at least some fine filtering ability, which should be discarded at cleaning..

Well one suggestion..