How to check cleaning effect before treatment-process?

In the treatment process of aluminium – for example in anodising – a clean surface is very important. The following question often comes up: how can we check if an aluminium surface is free of grease and oil when it comes out of the cleaning bath? Certainly, this can be checked with analytical equipment in the laboratory. Fortunately, there are several ways to do this, which we would like to look at in this video.