Sometimes, we forget about servicing our hives or even don't get to them as often as we would like to.
A client recently told me about their experience where they were given 2 bee hives that have not been looked after for many years!
The comb is all brown and or even black. The super and brood are totally built up with bhur comb and even the queen excluder was propolised closed except for a few tunnel-like holes joining the two boxes.
When the client tried to open the hive the bees were extremely aggressive and hardly let up while they worked the colony. In this situation, the comb is so dark because over time the bees propolise the comb to make it stronger.
It is important to service your colonies at least once a year by removing the comb from two of the brood frames and returning them back into the brood chamber with little comb left up to the first wire. Everything else should be removed. Filter it, crush it and wax cakes to feed back to the colony a week later.
If you are a brand new beekeeper then get hold of a Blue book, or
Practical Beekeeping ebook and come on a beginner beekeeping course.