engine degreaser has stained engine!

Hi, I am selling my 1995 Barina and a guy at Autobarn suggested I use engine degreaser. He said to spray it on and wash it off, the can also said this. However, after using the degreaser and washing the engine well, a thick layer of creamy yellow paint like substance has adhered to the plastic pipes around the engine. I can scrap this off very slowly and scraping it of scratches the engine and leaves parts a dull colour. I tried turps as suggested by the manafacturer of the degreaser to no avail. I would really appreciate any tips as to how to remove this muck. I spent 4 hours trying to get it off yesterday and potential buyers are going to freak when they see the engine. Thanks in advance for any suggestions