Well if they hav'nt decomposed by now I'm sure that will help.If the plastic slider is still in place just use a small allan key in the hole and slide the mechanism up or down depending if it is fitted L/R handed. If the slider has dropped inside then use the allan key and a pair of molegrips. Place the right angled end of the allan key into hole and clamp the molegrips to the other end then with the angle end facing away from the keep wiggle about till you locate the notch in the locking bar then push it up or down again depending if its L/R handed to release. You should then be able to turn the mechanism to unlock. It sounds simple but I've just done it for my daughter and it took me all of three minutes.
Well if they hav'nt decomposed by now I'm sure that will help.
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