A cathartic experience: There's nothing more exciting for a conservator such as participating in a chemistry course. We go there with a certain respect (or maybe fear) and the will to be acquainted to a new miraculous reactant that will change our life. The poor conservator will poorly be able to discuss one to one with a chemist, either about the reactions that happen during the restoration treatments or along the inherent ageing of the artefact; and yet we must call the chemist into question and keep this dialogue alive. But thanks to Richard Wolbers I made peace with chemistry and their scientists.