"Oops- d-did I say that out loud?" [He squeaks. It's so hard to turn off speaking nefariously, when that was the only way villains commanded respect.] "Habit. Habit. Sorry."

[There is groaning now, and it's coming from more than than Flug, not that the bothered Paper bag appears to notice. Hrnnn. He needs to salvage this. He raises his arms placatingly.]

"It involves one drop of liquid onto litmus paper. Measures how acidic something is. I-if it's more corrosive there is less chance any form of virus can survive! More evidence it's safe to reattach."

[But if you want to just eyeball it and guess, be his guest!]

"O-or we can try something else?"