Oh you can use artic silver. You just made it sound like thermal paste made the project a no go. Any thermal paste will work. Mine was new when I put a new hard drive and DVD drive in mine, then a lightning storm in VA killed the ethernet port on it. Apple replaced for free ( the motherboard, as the tech spun a great story to get me a replacement ). I then took it apart again to max the ram. That fan needs alot of cleaning for sure. Never took long to get dust, as it has alot of surface area for draw but one exit.