The common plantain is commonly seen on roadsides, lawns, cracks in sidewalks, etc. They're not a very pretty plant but they have a long history of medicinal uses, treating minor wounds, sores, and bites to promote healing.

This is my recipe for making a simple salve from plantains. I had a mosquito bite so I applied some of my salve to the bite ... and the itchiness disappeared almost immediately. This stuff really works!
Materials
Plantains
1/2 c. coconut or olive oil
1 oz. grated beeswax
Method
First, pick your plantains. I packed a small ziploc bag with plantain leaves (you should shoot for the less bug-eaten ones, and preferably you should pick them a little ways away from a roadside, since the chemicals from car exhaust can make roadside plants unsafe).
Next, wash them thoroughly and get the dirt off. You'll need to dry them out until they're slightly wilted, to reduce the moisture going into the salve. I just let them dry off on a cookie sheet overnight, and that worked perfectly. You can also heat them gently on the lowest heat in your oven (although I haven't tried this).
Now, you have to infuse your oil with plantains. I'm told olive oil will also do the trick; I used coconut oil. You can either combine the plantains and oil in a jar and let them sit for 6 weeks ... or cook the plantains in oil on low, low heat. I used my crockpot, and let it cook on low overnight. By the time I woke up the next morning, the coconut oil was a deep green. (also, it smelled pretty tasty while it was cooking ... kind of like spinach!)
Strain out the plantain leaves (which for me were cracked and brittle at this point) from the infused oil, using a cheesecloth or fine mesh strainer. Heat the infused oil (again on low heat) in a small saucepan. Add a bit of grated beeswax at a time until you reach the desired consistency (to test the consistency of the salve, dip a spoon into the oil/beeswax mixture and then let it cool. Then you can touch the salve on the spoon to see if it's the right consistency. If it's still too liquid, add more beeswax; stop before it gets too hard).
You should end up with about a half cup of salve; have a few spare tins or jars ahead of time to fill up with salve.
When you have an insect sting or a cut, apply the salve liberally to the affected area. You should feel better in no time!
[I'll be adding a picture of my final salve product when I borrow my boyfriend's camera ... it's coming!]