Dish Washer

I have a whirpool dishwasher which was not used for many years because th rats had eaten the wiring, Recently a friend fixed the wiring and it started working,
However we than noted that the water jet was not working because the entry, which is in the sunken part of the machine, was completely clogged by cockroach droppings which has hardened and cannot be approached for physical removal, Is there a chemical for removing the same ?
Furthe I have noted that the PVC duct that returns the steam for drying is also eaten by the rats in a couple of places . Is it possible to fix it because this is a old model and I do not Know if Spares are available. If any one knows of person who can do this or give me details of site where I can search for spares I will be most gratefull,
collin.pereira@gmail.com