Regular inspection of exhibition and storage areas makes early identification of insect attack or mould growth possible. What to do then is the subject of this contribution. In the case of insects, it is recommended that they be identified first of all. The possible reasons for their presence and the extent to which the collection has been infested should next be ascertained. Materials for treatment are discussed. In the case of mould growth, rapid intervention is even more essential. What should, and what should not, be done, whom to ask for advice and which materials should be used are considered.