answer: #Person2# tells #Person1# that they check the metal casing, the brushes, and the canvas belt regularly.
documents: #Person1#: What sort of problems do you have with these machines?
  #Person2#: They're quite complex machines and they have a lot of different components. We need to check the metal casing regularly for any signs of corrosion. We also check the brushes once a fortnight to make sure they aren't worn down. It's important to make sure everything is properly aligned and we adjust it if necessary. There is a canvas belt at the end of the assembly line. If it gets wet, it might rot so we check that regularly too.