DIY cleaning worked fine for me!
Or you can order online - not sure if the Costco site offers them, but I have seen wax guards and domes on Amazon - just need to get the correct type for your Hearing Aid model.
Just FWIW: the receiver contains a copper coil which isn’t hermetically sealed. If you find something that liquidises the wax and let it dry on the receiver filter you risk subsequent condensate/perspiration/earwax mixing with it and forming something that is quite aggressive to the components.
Given how cheap some varieties of wax guards are, especially the Mk1 Cerustops, the economics of cleaning them over outright changes makes no sense.
The “Elephant Ear” is the product that my doctor uses for ear cleaning: Elephant Ear Washer | Dr. Easy Medical Products | Doctor Easy. So, I purchased one of my own a few years ago. I just put a few ounces of Docusate Sodium Liquid (available at Walmart) in the bottle first, fill the bottle with warm water, and it is ready to use. It works great!