For each useful and expensive chemical a specific method exist.
Proteins are useful chemicals that you obtain from food.
System restore can be useful
Because you've used up the nutrients, protein, and "fuel" your body needs to recover. This is the reason Gatorade is so useful.
A glow stick is only useful when it is broken, as this allows the chemicals inside to mix and produce light.
Many plants proved useful for this purpose.along with chemicals.
Your question is not at all clear. It would be useful to know what system you are talking about, what chemicals you are concerned about, and what salt water has to do with this. But in general, chemicals can harm systems. Some chemicals are quite dangerous.
Data Recovery tools can be incredibly useful. They can recover data and files often after they have been lost or corrupted. However, they do not always work.
Postpone and cover with reasoning and chemicals.
Chemical stains make light microscopes more useful by showing specific structures in a cell.
If a Pokemon knows that move use it and in will heal itself
This depends on which chemical you are referring to because different chemicals are beneficial in there own ways.
Gas has chemicals in it so it well affect you're lungs