Some coils activate a tightly grouped cluster of switches, especially those
in the cabinet bottom. When you move them to take a look and clean or
adjust them it can be very hard to judge if a switch is opening and closing
with proper contact because you see the switches behind or around it at the
same time. Fold or cut a small piece of bright white posterboard to slip
behind the contact you are working on. This makes it MUCH easier to see the
clearance between the contacts you are actually working on.