Okay, this is a good project if you like alchemical transformation type activities: The making of Lime Sulphur.
You take white lime…
…and sulphur…
…with water and boil them together for one or two hours…
Until you get a dark red-brown liquid that smells of rotten eggs…
The concentration I use is 115g per litre of white lime (calcium hydroxide) and 192g per litre of sulphur. So to make one US gallon (3.785L) I use 435g of lime and 725g of sulphur (more or less without being totally anally retentive).
Put the water in a pot that you will never use for anything that will come in contact with your insides ever again (also, ask the missus for permission, otherwise you’ll be in trouble!). Once it starts boiling put the lime in, mix well and then add the sulphur. Boil for one to two hours. After it turns red/brown let it cool down and using a funnel with some muslin, filter into a bottle of appropriate size for storage.
This stuff is poisonous and caustic and will cause all manner of injury (even death) to you, your loved ones, your pets and anybody/thing else if you do not act responsibly with it. Wear gloves, protective clothing, a mask and boil it outside of your house; label it clearly and keep it out of reach of children or any other people or animals that shouldn’t be messing around with it. If you are an idiot and have a problem behaving responsibly, you should not be trying to make this stuff…go buy a quart of it from Amazon instead!
Lime Sulphur is good to spray on dormant trees to combat fungal infections of different kinds, as a pet dip against mange, ringworm, fleas and assorted parasites, and as a doctor, I would probably use it on myself if I got scabies or lice (though I’m pretty sure that this stuff is NOT approved for human use…but I like sulphur). Please note that it must be diluted to appropriate concentrations, which is different for every purpose, before use. If you are willing to make it, then you must also be willing to research how to dilute it appropriately.