I find, the older it is..... the longer it takes to work.
The solution will give of some toxic fumes over time ?
Alodine is a combination of Hydrofluoric acid and hexavalent chrome. Hexavalent chrome is a really bad chemical. Remember Pacific Gas and Electric and Erin Brockavich. Be very careful with storage and disposal. Read the MSDS on the material. Do not dispose of it down the drain. You could go to jail for that action.
Just a warning!
Tyler
A&P