A close friend owns a bar and had a line of screen printed shirts (8 screens) around ten years ago. When the man who did the screen printing passed away, his widow gave our friend the screens, which he stored in a damp storage room. Although the screens and frame are covered in layers of dirt and mold, the screens don't appear to be damaged-there are very few pinholes or other marks that would need to be masked-and he wants us to begin printing the line of shirts again. I have hesitated to attempt cleaning the screens as don't want to damage or remove the old emulsion while cleaning the grime and mold off. I have read some tricks like taking them to the car wash, vegetable oil, mineral spirits, etc..., but I am not looking to reclaim them just make them useable. What would be the safest way to clean them without damaging the design?