washing out cyanotype...purple hazy bits?

Hi there,
I'm new to this site and I have been creating some cyanotypes with some large format pinhole negs I made.
I made some contact prints and on my prints there are purple /magenta-ish hazy bits in the emulsion .... does anyone know what these are? Have I not washed out my print enough? is this residual chemistry? Can I get rid of it? I could have printed these on older coated paper...has anyone had any experience with this before?
any advice would be appreciated!

thanks!

Cyanotype is sensitive to several things.
Which solution are you using, the traditional recipe or, Mike Ware's improved.
Which paper are you using? Mike's recipe doesn't like papers which are buffered to make them non acidic. The print will develop but will fade away during the dry down process
UV source?
Exposure? To short, and your precious cyanotype will come off in the wash!
Coating? I use a cotton wool ball dipped into the solution and wipe across the paper, I then wipe excess off using another ball, stroking in the other direction. I usually split a ball in half and discard both pieces after each operation. Contaminants can be lifted from the paper or the surrounding area.
Hope this helps. As a start have a look on alternativephotography.com/cyanotype there are some excellent articles on that site.