There's a trick to drying burdock leaf.
You pick the leaf of any burdock (our most common one is Arctium tomentosum, so I pick that) - piece of cake.
You spread them out to dry - easiest thing in the world.
A few days later you check on them ... they're a single flat sheet, and the ones that haven't gone moldy are now black, dark brown, light brown, yellow, light green, and dark green, from the middle on outwards.
Right, so that didn't work, then.
No, what you do is this:
Pick nice healthy leaves - I prefer smaller ones for some reason, but if you like, go for the largest there are.
Cut off the stalk.
Cut the center vein a few times. If the first pairs of side veins are large, cut them, too. However, when you cut, do it so that the veins will support the leaf when you hang it up on a string, because that's the next thing you do:
Thread a string through the first hole you cut in your burdock leaves, the one nearest to what used to be the stalk.
Pic: Burdock leaf, drying on a string.
Hang'em up to dry, either 10 leaves to a string on whatever doorknobs and similar are available to you, or all of them on a single long string that you tie across a corner of the room, or something.
Now, when you check on your leaf a few days later they dry a nice dark green (grey on the underside), and they don't stick all together in one large mat.
Uses, well, I use it instead of burdock root. The leaf is bitter, and far more diuretic, but it's still nice medicine. Think psoriasis and overactive liver. Think hepatitis A, B, C, D, E, ... . Think "works with solvents". Burdock. And dandelion, root or leaf.
Update: if you hang them 10 to a string on a doorknob you'll need to go in and separate them about once a day, until they're fairly dry: gravity gets them too close to each other.
If your string is strung horizontally (or nearly so) you can forget your burdock leaf until dry: the leaves don't bunch up and dry to a nice gray-green.
Related entries: Burdock root - Burdock seed - Burdock stalks