Discard Unused Solutions

Tube with hair product
Photo: Mile Atanasov/Shutterstock
Q: Why are you to discard unused solutions (waving and neutralizer) after using them? I have very short hair, and my hair grows very fast. I never use all of the solutions when I do a perm and because of that I usually go to my hairdresser.
But I have always wondered why and what damage would it do after being stored away? My thought is it loses its' ability to do the curling and stabilizing am I correct?

A: That is partially correct, but there are other factors to consider depending on the particular brand of perm you use.
In many perms the main consideration is the fact that the perming chemicals will lose their potency after opening and exposure to the air. However, there are some perm formulas that are "self-heating" or require an activator and which could continue to react if stored away.
Even if you managed to find a means to re-cap the mixed chemicals, the reaction would give off by-product gasses that would build up and potentially explode the container.
Aside from weakening solutions and potentially dangerous build-up of chemical heat, there is also the matter of caustic fumes that are impossible to control and would constantly be wafting throughout the area where the remnants are stored.
See also:
Perms and perming hair
Do hair products such as gels, creams, mousse expire?