JonB,
All the OHM meter is reading is an Open Circuit, bridge blown or a Closed Circuit, bridge connected. A Digital VM will not cause any probs, been using em for years. How do you think that John Carr found out that the bridges were connected to the so called 'Unused Pins' actually the BP-FID, he used an Ohm meter.
Obviously you must use the Acetone sparingly, on the end of a q-tip. Keep it away from the core and the resistors.