The hread about freon, etc. was very educational.

Brought up a question bothering me: How can one tell if FE is still OK?

Mine is a very old Kidde, big red puppy; A.B.C. Indicator is still in the green, albeit leaning toward the left (recharge).

Has never been used(thank goodness!)

However, I don't want to find out the hard way that it is over the hill.

Can I squeeze the lever a little, to see if it works? Don't hit me; I'm just ignorant!

The new ones that size range from $40+ on up. I'm not trying to nickel & dime my home's safety; just want to know if there's a way to test this.
If the test shows it's still good, fine. If it shows no good, at least I know what to do, $$ notwithstanding.

Any help appreciated.

HB