In a dry climate, this won't take as long. In other climates, longer. In other climates you may resort to your oven, which is not recommended because the oven gets to essential-oil-destroying temperatures. But with care it can be done.
This is my desk, called The Ocean, because it is big. These are the removeable screens people used to use in double-hung windows that had no screens. I found them on a garage sale. You can see they can be narrow (the upper one, with the pineapple weed on it) or wide. Use what works for you!
The lower one has whole stalks of yarrow at the left and basal leaves of the same plants on the right. The big leaves on top are comfrey. I figure if I can break them and hear them, then they are dry enough. I live in a humid climate, so I'm careful about this dry-enough business.
First I stripped the basal leaves of leaflets, creating a pile of material. it took a little while and smelleed all yarrow-y. This is a big benefit of cleaning your herb: you learn the smell of it. It's lovely.
Then I took the big stems of yarrow and stripped off the leaves (leaving them intact) and popping the flowers off the umbel stems. Here are the yarrow flowers in the leaf material.
Those big leaves are comfrey leaves. I decided to pinch them into crispy bits to allow the goodness in the herb to get into the salve.
I like big roomy ceramic bowls for small bits of herbs. Pie plates work well, too.
I pinched off pieces of comfrey, generally (generally) avoiding the middle vein, or rib. That tougher plant material doesn't let go of it's goodness easily, and is really built for support, not herby goodness. But there is certainly some rib-ness in my pile of herbs tonight! It makes noise every time you pinch some off, that's how dry it is.
There are many, many, many uses for plants. Not all of them are about food or making cord, or making a building. -- What the heck am I talking about?
Yarrow stems were used in antiquity by the Chinese for fortune-telling in the I Ching system.
Hmmm. I bet they took the umbel ends off. Just sayin!