Maybe I'm the only RE-20 owner that didn't realize that the foam inserts in this mic (pop filter, body liner, etc) would, over time, degrade into a mix of black goo and plastic powder.
I came across some internet posts regarding the degradation of foam in the RE-20 (and RE-27 for that matter). Fortunately I had the itsy bitsy teeny hex wrench needed to release the windscreen (0.035"), unscrewed the screen and was presented with "pepper" falling from the mic along with a pop filter that had turned to a semi goo. I bought this mic new about 20 years ago.
E-V will rehab an RE-20 for a flat fee of $269.00, but they don't just replace foam, they replace the entire guts of the mic. Included in this is a new electronics unit (which they started using after a redesign in 2011) that has been reported to have some issues picking up buzzy electrical stuff from its environment. Didn't want to go there. So, I printed instructions for replacing the foam and ordered the three pieces needed from Full Compass (under $15)
Did the job today. E-V did NOT build this mic for easy maintenance. But with some care, it isn't that bad — took maybe 3 hours and a couple cups of coffee. I did get lucky that none of the internal wires were damaged/broken as I was taking everything apart.
Probably worth a look if you have an RE-20/27 that's been around for a few years, or bought a used one of unknown provenance from eBay. Here are a couple of links to good instructions on how to go about it, what you need, etc.
https://www.jeffgeerling.com/blog/2017/refurbishing-classic-microphone-electro-voice-re20https://messageboard.tapeop.com/viewtopic.php?t=81171
