Lemons that have gone bad haven’t completely gone to waste. Ants, roaches, and fleas actually hate the smell of lemons.
So, if you’ve got a pest problem, just place small slices of lemon peel on windowsills, in doorways, and near any cracks or holes. The scent is enough to drive those critters away.
Lemons can also be used to remove mineral deposits that build up in your tea kettle. All you have to do is fill it up with water, add a handful of thin lemon-peel slices and bring to a boil. Afterwards, let it sit for an hour, drain and rinse, and your kettle will be as good as new