If you can't open them up, another method is:
Put 100 bb's in a plastic bag
Add a few drops of silicon oil to the bag
Mix it up
Load those bb's into the magazine
Eject them back into the bag.
Load them again.
Eject them again.
Load Fresh BB's.
Test in your gun.
Ár skal rísa, sá er annars vill
fé eða fjör hafa. Sjaldan liggjandi úlfur
lær um getur né sofandi maður sigur.