I just did this. I ordered Aero refills. Ripped the existing blades out of the assembly and that allows you to squeeze the metal bars together to remove the end cap. Then (it takes time) lubricate the new blade refills and slowly pull them through the assembly. once the entire piece is filled out, trim the access and snap the end cap back on. took me about 30 minutes to do both, 20 mins on the first one trying to figure the best way to disassemble.