Not really measurable.

After a marten had settled domesticated in the engine compartment, I have carried out an engine wash with detergent. Then use the Duftmarkenentferner and thoroughly sprayed the engine compartment, underbody and adjacent parts. Leave for a few minutes and treated with running water.
The park area itself, I have dealt with. In addition, scattered with fine sand to determine traces.
Everything like the description it wished.
On the same day I have an electric Marten defense (ultrasound) installed in the engine compartment.
Lo and behold, 3 days later, it was the marten matter. The sand tracks were nicely visible in the engine compartment.
Whether removing the fragrance brand really works, eh undetectable because it is not visible and so the manufacturer has also clearly stated that this has no preventive property before new or rear attack.