Since I have not been jaded yet by the endless maintenance required to keep the ports looking nice on my new-to-me R25, I wanted to clean my ports at least so that I can later say "never mind, that's too much work"! So I tried many things to get my ports clean after they probably have never been cleaned since 2008 when it was new. None of the cleaners worked for me so I took drastic action and used muriatic acid to clean them. To do that, I removed the inner port parts as an assembly by removing the acorn nuts on the outside and flat head screws on the inside and pulling out the inner part. That was relatively easy once I knew it would come out. The outer ring stayed in place because it was bedded against the fiberglass on the outside. I then disassembled all the pieces and one by one submerged them in a solution of water and muriatic acid in a ratio of 5:1(with all the precautions: work in a well ventilated area, use gloves and a mask, and add the acid to the water not vice versa). I let it soak for some minutes (even the part with the glass) and then used a tooth brush to remove anything left. On exceptionally stubborn areas I used a 2:1 mixture and applied preferentially. At this point, the parts were corrosion free but mottled and stained. So I used 00 steel wool and then 0000 steel wool to make it pretty. As a final polish and protector, I finished with Brasso. For the outside ring, still bedded in place, I used the same technique except rather than soaking it, I applied the acid with a tooth brush and let it drip down into a towel I held under the port. That was more difficult than soaking but I didn't want to deal with rebedding the port. I also used the steel wool on the outside but very carefully cleaned up the fine slivers that dropped. That was a risky deal since anything left over would rust and mar the fiberglass, but I took the chance and did not have any problem. There is much debate on the web about using muriatic acid to do this, but I found it worked very well and has no lasting effects that I can see (at least in the 2 months since I've done it).
After the major polish, I cleaned the outside every 2-3 weeks with Brasso - the inside has stayed pristine. One caveat though - the boat has not been stored in the water and is located in super dry Colorado........so it's much easier to keep clean. I decided I wanted to cover the ports when not in use to keep them dry, so I found rubber dog dishes at Walmart and attached a suction cup to them such that the dish is held against the outside fiberglass with the suction cup attached to the port window. I didn't get any experience with that however before I put the boat in storage, so time will tell if that's a viable solution.
It took me a long time to decide to remove the ports, but that's clearly the way to go if they are at all difficult to clean. In fact, I will now not hesitate to remove them even for minor cleaning if needed.
I know.....many out there are saying "just wait - you'll see how much energy it takes. This won't last long". But they look sooooo marvelous now - especially the inside. And since the boat is new to me, I was willing to put in the effort required the first time. Time will tell if I feel the same way in the future.
Doug