Throat irritations, coughing, for whatever the cause, relief is quick and lasting from sucking on just one poplar bud, don't know all the medical reasons, but that is fifty years at least of personal observations. Poplar is an aspen tree, the original aspirin was made from this tree, I believe.
The process is simple, pick the leaf buds just before they open, when you see little drops of sap on the outside of buds, that's when I like to pick and dry them. Sticky finger job.
The fresh, but not wet, buds can be put in clear jars half filled and covered over by a third more, in olive oil, put a cloth over the top, set in a warm sunny window, six weeks, once a week, stir gently with a stick. Now you can use the oil, or strain out the buds and make a salve.
This is one way to make salve; grate bees wax, heat up the oil with a bit of grated bee's wax on the surface, it will float until it melts, as soon as it melts, keep the oil mix at that minimum temperature. This is where you can decide how hard you want to make your salve, too soft it will liquefy on hot summer days, if it too hard, it will be hard to apply and feel oily on your skin, this greasy feeling is due to excessive bees wax. Hard salve may be good for a lip balm which you can also make, but hard salve is not great for a general skin application, as it may remain oily longer than desired. The bees wax molecules are bigger than olive oil molecules and do not absorb as well, in other words don't use more wax than you need to. To get the consistency to suit yourself, requires melting a bit of wax, stir gently as to not mix in a lot of air, put a drop on a cold plate out of the freezer, it should solidify pronto, feel how hard it is, if it turns into mush, add a little more wax, work your way up to the hardness you like, then pour into small jars, let solidify, put on lids and its good for years. The antioxidants in the resin prevent the oil from going rancid. Want to know more, google it.
Leaf bud is best, avoid the buds with cores in them that produce the cotton balls, they turn black inside when dried, they are mostly on the ends of the blanches, open buds till you know the difference, it will be obvious, after a bit of picking, and missed ones can be picked out later when you spread them thinly to dry, I dry in trays, screens are not recommended, sap is hard to remove. Waxed Paper in trays works fine.