When bees secrete beeswax, it's white. As bees walk over the comb and fill it up with nectar and pollen, the wax turns various shades of orange and yellow. I can always tell the difference between my Spring and Summer honey because the Summer honey is bright yellow and so is the comb. It's almost neon, it's so bright with a slight green tint (I kid you not!).

When you leave comb in the hive for months, especially in the brood section, it will start to turn dark brown. This is mostly from propolis. Propolis is plant sap. It is super sticky and usually various shades of dark brown or a reddish brown (but not always). It stains not only wax but also clothing. It's why my white bee suit has brown stains all over it.

Why you want to remove old, dark comb from the hive

If the comb in your frames is getting to be a dark brown, it's best to remove that comb and not put it back in the beehive. There are two reason why I recommend doing this. The main one being that I put treatments into my hives once a year. Beeswax is very porous and the wax absorbs these chemicals. I don't believe the buildup of these chemicals is a good thing and prefer to cycle out this wax.

The other reason only pertains to the comb that is in the brood boxes. The brood cells are lined with propolis and get a lot of traffic from bees walking over them to feed the brood (baby bees) all day. When the comb gets dark, I mean really dark, these cells can get smaller from the buildup of propolis. Although I see some hives use this comb anyway, I also see hives begin to abandon this comb, if they have room to build comb somewhere else. I prefer to take this comb out and give the bees room to build new honeycomb.

Removing old, dark comb is by no means a requirement. It's one of those things I do because I have a hunch it's the right thing to do and so I do it. Some beekeepers never remove the old comb and some beekeepers use this comb as bait in swarm traps because they say it lures bees!

Just to clarify, when I talk about old, dark comb, I'm not referring to comb that's a darker brown. I'm referring to the comb that is almost black. It's covered with so much propolis, if you were to fold it, it would just snap, its so stiff and hard.

A good time to remove the old comb is in the Fall before you close up the hive for Winter or in the early Spring when the queen has just started to lay again. If you live in a warm climate and there is always brood in the hive, you can remove frames of old comb once the bees have stopped using it (sometimes they abandon the comb) or when there is a new queen and the comb is empty. 

Something I always struggled with was what am I supposed to do with this old, dark comb?

I tried melting this old, dark comb down the same way I do with the beeswax I have from harvesting honey. This didn't work well. Dark comb, when melted, smells pretty bad, you get very little wax from it and the wax is a shade of brown which didn't lend itself to the candle molds I had of pineapples and palm trees.

Despite how much I hate throwing anything away from the beehive, I resorted to just throwing this honeycomb out. It wasn't worth the electricity to melt it down for 3 hours if all I was going to get was a pot of floating propolis casings and 5 ounces of brown wax.

Finally, I made myself a solar wax melter. I read about a solar wax melter you can make from a cooler that takes 5 moinutes to make. So I made my wax melter, threw a piece of old comb in there and just a few hours later I had a little piece of beautiful, yellow beeswax! I was so excited! I wasn't wasting hours of electricity and my time melting wax and water and straining and it was yellow again! 

I only recently made my first solar wax melter and the only thing I can say is "What took me so long?!" These things are amazing! Not only is it a great place to throw little bits of beeswax from an inspection week to week, but it's by far the best way to clean your dark comb. When the comb is in a solar melter, the wax melts and goes down to the bottom and the propolis casings stay up top in your basket. The propolis doesn't mix in with your wax and your wax ends up a nice shade of yellow/orange.

I have been told by beekeepers that you can also melt your wax in with water at a high enough temperature that it causes the wax/water mixture to bubble and this will also separate the wax from a lot of the debris and propolis but I don't recommend doing this. For one, beeswax is flammable! It has to be done outside and you're still using a lot of electricity and since you're outside handing wax at high temperatures you should be out there making sure everything is ok. This is a lot of time wasted. Don't do this.

Solar wax melters are easy to make. All you need is a styrofoam cooler, aluminum pan, hardware cloth, and piece of glass or plexiglass (an old fame works well). See the video below on how I made a solar wax melter.

The only time a solar wax melter isn't the best option for your old, dark comb is if you are in an area that gets very little sun. The dark comb, especially, takes awhile to melt. The melter needs not only sun, but sun for at least 4 consecutive hours to properly heat up the box to the temperature needed to melt the wax. Without this, your melter is useless.