Bottled Lemon Juice

It will Keep for a year.

From 1922:

To every quart of lemon juice add 3 lb sugar. Put the mixture into a jar and place the jar in a pot of water. Bring to the boil stirring well until the sugar is dissolved. Do not let the sirup actually boil. When the sugar is quite dissolved bottle and cork the syrup. It will Keep for a year.