Its all my bad. I found my terrarium aquarium alongside the road, picked it up and stuck it in the barn. After a year or two in the barn, I admit I did not do a good job of cleaning it before use.
And now, another year on, my terrarium full of drosera and orchids is growing some greyish mold on the inside of the glass. Any thoughts on how to clean it without killing the occupants or taking it all apart? I'm going to try some fungicide on a cloth then figure out how to clean the glass. Windex on a cloth? I use windex to clean the inside walls of my greenhouse; it hasn't harmed any plants yet.