I would keep an eye on the part dead center of the last picture. The yellowish green stem in particular. This could be a problem. It could either be the beginning of a corked stem or a couple diseases common to Holiday cacti. Is it soft or mushy? Keep an eye out for blisters on this stem or spreading of the discolor. If blisters occur it is Edema, which will kill your plant if you don't take action immediately. Edema occurs when the growing media remains moist and the greenhouse air is cool and moist. The plant roots absorb water at a faster rate than is transpired through cells causing the cells to rupture. This rupturing of the epidermis and the inner cells causes the raised, crusty appearance on the underside of the stems. This can be fixed, however. Fusarium wilt is also common and if it spreads, with no blisters this could be the problem. Fusarium is a virus which colonizes the water-conducting vessels (xylem) of the plant. As a result of this blockage and breakdown of xylem, symptoms appear in plants such as leaf wilting, yellowing and eventually plant death. Fusarium is used as an herbicide in South America, where Holiday cacti are native to. It is usually fatal to your plant, unless you can take cuttings of the noneffected areas quick enough. I'm not trying to scare you, but make sure you keep the plant's soil as dry as possible until you can repot. If it were my plant, I'd take a few cuttings as insurance, then either take it back, or repot in new soil and pot immediately after a good bleach bath.

This rarely happens with me as I am known for my neglect when it comes to watering, but this winter, I had a Dog Tail Cactus in my cool greenhouse and it got cold damp "feet" and the tips began to turn brown eventually traveling back towards the center of the plant. I took the plant inside the warmth of the house, cut away the rot, and placed the plant in good light just above the baseboard heat to warm, and dry out the soil a bit. It now it is doing well with new growth, and I am very happy that I caught it in time. I'm sure you will be able to save your beloved plant, but taking cuttings as insurance is a good idea. Hope all works out well.

sambah006 Unfortunately Alkyd primers don't cover tannin and stain as well as BIN. I am redoing dark stained oak cabinets and after multiple coats of both primer and paint, the stain will bleed its way through. The only thing so far that has calmed this is BIN from my tests. I know that paints and primers (Latex/Water based is what i'll call alkyd, or anything in the same types) have come a long, long way compared to just a few years ago. The ways when people would stick to oil based because it worked better. Well the water based have come a far way, but they still don't have BIN blocked on the most stubborn of stains. I also think my scenario is just an extra difficult one, unfortunate for me and its making a lot of extra work. For regular projects, an Alkyd may do the job just perfect without any of the harshness BIN brings. I would try to go the water based route every time over the more chemical laden one. When it comes to stains and odors on walls for instance (Not stubbor tannin and wood stain), I'm sure the water based/latex/alkyd products have that covered no problem by now.

Only way that I know of that avoids coffee aroma from brewing is a cold brew system which makes a concentrate. The brewing is done in the refrigerator with cold water. The concentrate results in a less acidic brew, which some people prefer. Cups (or more) of hot coffee are made by adding hot water and/or hot milk to the concentrate. There will be some coffee aroma at that point, but much less than from any hot brew system that I know of. The "Toddy Cold Brew" is probably the best known example of this. Here are some links: https://www.seattlecoffeegear.com/toddy-cold-brew-system http://www.amazon.com/Toddy-T2N-Cold-Brew-System/dp/B0006H0JVW There are other cold-brewers from the likes of Hario, Oxo, Sowden, Primula, and several others.