Base and base plate
The base of the machine, if you let water stagnate in the drip tray, can result in the formation of rust. The phenomenon affects both machine with chrome base that painted, although the latter phenomenon is more frequent and occurs even in the absence of particular neglect. If the rust is very deep can puncture the metal.
The phenomenon of rust can also affect the sub base. Is mainly due to condensation that can form under the base and is accentuated if the machine is kept unused in humid environments.
In the case of a painted may also depend on the formation of rust in the drip tray.