I maintain the humidity in my workshop below 30% at all times, yet, rust has developed on some of my tools that I didn't wax (Starrett squares and straight edges). Tools in question are less than 4 months old. Any theories? Its not the humidity monitor, as it has been professionally calibrated. Currently, its 96% humidity in the ambient area outside my workshop but only 28% inside the work shop. I run both a dehumidifier and A/C constantly and the shop is very sealed very well. My shop is 12 x 24. I've checked for micro-climates where the rusted tools have developed as well, so that isn't the answer either. I'm perplexed.