The humid heat of summer provides an ideal environment for the growth of mould and mildew. An electric dehumidifier can help reduce moisture, but it has two disadvantages -- it uses energy and placing one in a room may not help with cupboards, especially if the doors are closed. There are two methods for making your own homemade dehumidifiers from materials you probably have around the house. They don't use electricity, are unobtrusive and can even purify the air while also removing moisture.
Drill three or four holes in the bottom of a yoghurt container.
Cut a round piece of fibreglass screen that will cover the bottom of the container. Drop the screen in and push it down to the bottom. Cut another round piece of screen that will fit around the top of a second container with about a 2.5 cm (1 inch) overlap, and then secure it to the container with an elastic band.
Fill the first container with granulated rock salt -- the type that is used for melting ice on roads. Place the second container in the corner of a cupboard or wardrobe and put the one with the rock salt on top of it. The salt will condense moisture in the air and turn it to water, which will drip into the bottom container. Empty the bottom container at regular intervals.
Fill a third yoghurt container with charcoal to make a dehumidifier that will purify the air as it sucks moisture out of it. Drill several 1.25 cm (1/2 inch) holes in the lid, put the lid on the container and position it in a strategic place. Replace the charcoal once every few months -- more often if it is especially humid.
Increase the effectiveness of your dehumidifier by using a desiccant such as silica gel instead of salt or charcoal.
Protect the container of salt from tipping over. Salt is corrosive and may damage your floor or carpet if left for an extended period.