Humidity is around 100% for at least 9 months of the year in my neck of the woods, I feel your pain. Growing in the southern part of the US is brutual indoors and out.
My current SOP is to use compressed air to blow the fins out every 3 months to avoid the use of chemical detergents. 50 psi blows everything out of the fins, its messy but allows you to rinse the cooling fins with water right down the drain tube. I use a portable 13 gal air compressor from good ole Harbor Freight.