I would like to suggest that wood ash should be added into the game.
This can come in either a waste slot in the campfire or it could be acquired from breaking a burnt campfire. Alternatively, you could get it by either burning down trees or failing to make charcoal.
Wood ash is known to be very basic and has a number of real life uses that can be added to the game.
1. Soap
Historically, the ashes from burning firewood have been added to water and then mixed with animal fat to create soap. This could be potentially used to remove dye from cloth or shields or other purposes if more dye-able items are added.
2. Fertilizer
Wood ash is used as fertilizer because it's high in potassium and it can be used as a renewable alternative to potash.
3. Pretzel bread
If a very small amount of wood ash is added to water, this is used to make lye, in where bread can be put in to make pretzel bread.
4. Leather
Lastly, if a lot of wood ash was added to water, this would be very basic to the point I think it could work as a substitute for lime-water when making leather.