Back in the good old days in the tropics...pre-aircondition....low watt bulbs were sometimes placed in wardrobes to reduce 'penicillin' (good one-markit). Later, a slim small-wattage heater called 'golden rods' were commonly installed. The idea is to create an airflow by the principle of convection heat and reduce humidity. Cannot say either was very successful as I often had to throw out fungus laden clothes.
The product my wife recommends is called 'Serap-air'. It is sold in most supermakets and is a gel that converts humid air to water. They come sealed and may last up to 1 month.....the instructions explain. I suggest for 2 months just double the amount you leave open.
Our casual maid who attends our vacant apartment in Jakarta, when we are in Bali, exchanges water-filled packets for new......as well as open all the doors and switch the A/C's to dehumidify for a couple of hours.
Our system has worked well.