I have been using Simple Green to clean resin off my blades with limited success, so I broke down and bought a product from Felder designed to remove resin. Yes, it was expensive relatively. But Wow does it work! The series of pictures below will show a 30 minute soak of Simple Clean versus a 2 minute soak of the Felder product. There is no comparison. Thought others might want to know. The product name is in German so I won't list it here but it is in the eshop as a blade cleaner. These are the Simple Green images
These are the Felder product. .
These are the Felder product. .