...what these symbols mean?
I have seen these symbols before but I didn't know what they meant and I didn't bother to find out either. Maybe I'm a laggard where this is concern but I was only enlightened last week so this bit of info is for people like me.
12M means you must use the contents of the tube within 12 months and 24M means you must use the contents of the jar within a 24-month period. It's as simple as that! I felt kinda stupid not having come to such a conclusion on my own but I cannot know everything, right?
It seems the contents will only be effective or remain fresh for that number of months from the time you open the jar or tube or what ever.
So check all your tubes, jars and bottles for that symbol. If it shows 12M and you are still using it after one year, you have to seriouly consider whether it is doing you more damage than good. Throw it away!