In order to find out quickly if a surface has been subjected to corona treatment, Ferrarini&Benelli are distributing a new line of non toxic pens called  Dyne Test Pen.

They are offered as an alternative to traditional inks, these too part of the product portfolio of the Cremona based company, and they are very simple to use. All you need do is trace a line of about 5 cm on the substrate to be measured; if the solution grips, the substrate has been treated, if though it breaks down into drops, the surface is untreated.