Hey............. my last name is Boyd and I'm from Canada too. Welcome.
You have 2 items in question, the coin mech and the slug rejector. Your rejector only carries dimes so nickles will be recognized as slugs.
I understand why you want it cleaned, looks like it has been spray-lubed which is not good for a rejector as it will collect dirt too fast.
Once you have it clean, set it on a level surface, drop in a dime and "follow the coin".
When it sticks, take out only the screws and part necessary to see what is blocking the coin path then re-install and follow the coin again.
Your pictures will help you determine original adjustments too. If all else fails ....................I send mine to Tom.