Although a Jodi-Vac consumer is expensive (~$100 on Amazon), it does a good job of cleaning up the dome openings plus everything else - and you can use it on a daily basis - you don’t have to wait three weeks, 2 months, or whatever. One needs to buy replacement filters for the device (direct from the mom-and-pop operations about $16 including mailing for a pack of 6, which should last 3 to 6 years). Compared to the cost of going to a premium audi, the cost of a Jodi-Vac is spare change. It is a good idea to pinch the dome slightly against the receiver when vacuuming the openings. Don’t think you could really pull it off - the suction is strong but not overly but that’s what my audi advised me to do. I have also been running the Jodi-Vac needle over the microphone openings on my HA’s to suck out anything like dandruff that might have fallen in there - but don’t actually stick the needle down into the openings - pass the needle around the switch fitting into the body of the HA as well.
BTW (edit update), although it’s not that loud, I wear gun muffs (ear protection) when using the Jodi-Vac as I have it on a table close by my ears. It’s basically like a fish pump with a nice tubing/needle/filter system. The design seems to be very simple but well-thought out. One could probably try building a home-made device but it probably would not be anywhere near as well put together. With time, some wax seems to build up inside the syringe needle tube that causes some resistance in reinserting the reamer pin. One can overcome this by taking the syringe needle off the filter tube and running the reamer pin through the back side of the syringe needle. Also, moistening the pin with a little bit of your favorite cleaning solution and reaming the needle tube helps clean it and make the pin slide back into the needle easily. Otherwise, you may find so much resistance builds up from a slight amount of gunk inside the syringe needle tube that you’re in danger of bending the reamer pin when you try to reinsert it in the syringe needle when you’re done vacuuming.