I have seen the tablespoon of cinnamon thing before. Not pretty.
physan 20 is really good for cleaning out mold and fungus from T tanks. Also, New era peat moss and New era vermiculite is actually sterile! So I suggest using a physan 20 solution( by that I mean a wet paper towel and a little physan 20 on the wet papertowl, or soak the whole tank in phsan 20 and water in a tub) to clean the p. regalis tank and then use the new era peat moss nad vermiculite. I use physan 20 for my orchids and T's that have mold in their tanks. It leaves no residue, so it doesn't hurt the T.
http://www.physan.com/
Although re-doing the tank is an arse pain for sure, it's probably the safest way to deal with the problem without putting your T at any risk at all.
A couple extra hours worth of work would definitely be worth a T still alive and healthy and not distressed by any added chemical whose effects we all can't be sure of.
Just my opinion.
Gonna redo the tank. lol. I will do the cinnamon thing though, just for kicks....
Thing with mold is that just cause you cant see it, doesnt mean its not there.
Removing just the moldy spots MAY leave undetected mold in the tank.
Hydrogen peroxide is also a way to treat small mold outbreak.
For example a moldy bolus, remove it and there is a small bit of mold left behind....spray with hydrogen peroxide and itll kill the mold.
I have not ever used this in a T enclosure, but peroxide evaporates very rapidly so I think it would probably be safe. Any opinions on peroxide?
Redo the tank completely and switch to fake SILK plants.