It is not often I plug a product, but I discovered this spray degreaser on sale for $2 in the reject shop. having worked on old bikes and oily cars for years, I have struggled to find a decent degreaser. I was amazed how well this stuff works! I used it on my cars oily head, one full can, waited a few minutes and washed it off with water. The head came up like it was new. The car has 230,000kms on the clock too.
I am not sure what the reject shop is called in other states, but look out for it.
(http://fjowners.com/gallery/6/1121_14_12_13_10_57_48.jpeg)