I’ve been meaning to get around to this project for some time; several of my neighbors had problems with poison ivy last year, and jewelweed (Impatiens capensis) which grows all over my yard is a natural remedy for the oils as well as reputedly being anti-itch in general.
Here’s a walk-through of what I did to make a very basic lotion; you can also use the same theory to make any other sort of lotion/salve/etc you feel like. Tinker! Play in the kitchen! Have fun! 
Step one:
Infuse some oil. Jewelweed is a very very juicy plant, so I began by hanging it up for a few days to dry, so it wouldn’t mold in the oil. (If you’re working with something less hydrated, or already dried, you can skip this step.)
Crumple up your dried leaves a bit, put them in a jar (glass is nicely non-reactive), cover them with oil (I used olive oil) and let it sit in a sunny windowsill for at least 3 weeks. Shake it sometimes when you remember! (You may notice that my 3 weeks turned into 9 months; as long the plant bits stay covered with the oil so nothing molds, this is fine.)
If you don’t want plant bits in your oil or your lotion, strain them out before you go on to the next step. (I had enough head space that I just poured off the top.)
Step 2:
Do not be like me. Clean your kitchen before working so you don’t have to take ultra-close-up photos in hopes of not embarrassing yourself!
Measure out approximately equal amounts of beeswax and your infused oil. Put the wax into a double-boiler to melt.
This is my improvised double-boiler; it’s a tea canister on top of a little metal trivet inside a small saucepan of water. I have lots of tea canisters, so I can save this one for next time & not have to worry about cleaning it out.
Melting! Look at that steam! Stir occasionally; I used a stray metal DPN that lives with my candlemaking kit, but go with what works for you…
While your wax is melting (this will take a while) set out the containers you want to use for your finished balm. (Always have more space than you think you will need; if you don’t fill it all up, no problem; if you have extra goop with nowhere to put it, this can be an issue.)
Once your wax is nicely melted, take your melting pot out of the double-boiler. (Use pliers or a hotpad if your container is hot! Don’t burn yourself!)
Add your oil, mix well, and pour it into your balm containers. Try to do this before it solidifies! Then let everything cool.
Troubleshooting: Once your balm is cool, if it’s too gooey, you need more beeswax. If it’s too hard, you need more oil. You can re-melt everything & tweak it, or you can make a note to do better next time.
When you’re satisfied, label your jars & enjoy! 
