How about this: Does the strength of an acid or base affect the ability of it to clean stains? So choose a type of stain, be it blood, coffee, ketchup, or all. Then, for each type of stain, use a strong acid or a strong base. Like HCl is a strong acid, and vinegar is a weak acid. So for a stain caused by 10mL of coffee, pour, let's say 20mL of HCl. Then on another stain caused by 10mL of coffee, pour 20mL of vinegar. Therefore, you're answering the question of whether it is the ability of vinegar and ammonia to neutralize that removes the stains, or is it something else.
Good luck!
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God grant me the serenity to accept things I cannot change, the courage to change the things I could, and the wisdom to know the difference.
-Serenity Prayer
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