The notion of the "processing of goods" usually refers to the following operations:
a) the working of goods, including their installation, assembly or fitting to other goods;
b) the processing of goods;
c) the destruction of goods;
d) the repair of goods, including their restoration and putting in order;
e) the use of goods which are not to be found on the processed products, but which allow or facilitate the production of those goods, even if they are entirely or partially used up in the process (production accessories).
(Regulation (EU) no 952/2013, article 5)