This is what is left of the naples yellow on my watercolor set after TSA chipped it off with a pair of scissors. The paint (after much use) had formed into a blade-like shape and was deemed worthy of investigation…. After several trips through the scanner. They dismantled the set, almost breaking it, but finally decided it was that little strip of paint that was the issue. After they took out the offending color, they gave me back the set and let me go. I’ve been flying with this paint set for YEARS with no issue. I’m still baffled as to what the issue was now.