paint question

so, I just got my 1982 Yamaha XS650 running after re-doing the fuel system. To understand my paint problem you have to know that. My pieces that are painted were spray painted by my father who did an amazing job, he used many coats and i believe a clear coat as well, it looks extrmemly good for spray paint. I had to clean the inside of the tank. We did this using phosphoric acid in the inside of the tank and letting it soak, which by the way does not work. We finally sprayed the tank out with a pressure washer and degreaser which works very well and then baked it in the oven to get rid of the moisture which also works very well. So, basically, oily hands left fingerprints all over the tank, and we baked it with the fingerprints and stuff. Stupid, I know but it happened. So I now cannot get the tank and some other parts clean, the paint shines but i cant get these oil marks and stains off. I am worried to try anything because its spray paint. I bought some polishing compound but I thought i would ask here before I used it. HELP, what can I do, I want to clean the paint and then apply some kind of polish or protecter because it does look good, its a nice even yellow. Sorry for the long post but i thought maybe a good explanation would help.