However, the university was closed between 1942 and 1944 by the German occupiers – during that time he worked on analytical chemistry under Paul Coremans at the Solvay S.A.'s central laboratory.
Sneyers took part in scientific research on the Ghent Altarpiece by Hubert and Jan van Eyck), examined and restored by ACL between 1950 and 1951.
[4] Philippot and Sneyers continued their collaboration on other works by Dirk Bouts, Hans Memling, Justus van Gent, Peter Paul Rubens and others.
He made contact with 67 specialists in 32 countries and showed them his studies, allowing him to take part in a number of ICOM conferences as well as to establish a scientific committee on stone conservation within the Icomos Belgique.
He also worked for five years with its architect Charles Rimanque, the first time a building had been wholly conceived and equipped for art and architectural conservation.