If you lift any of the green protective paint off the copper tracks with your alcohol, go buy some cheap girly nail polish, a bright colour!
This can be painted over any exposed areas of the motherboard/copper you need to repair, works well.
Also, if you have small sections of track that are suspect or badly corroded, buy a rear window demister repair kit from a local car spare parts/autobarn/repco. The silver conductive paint can be used to redo the damaged tracks for short distances. Wait until dry then cover with nail polish