After leaving some of my (water soluble) oil paintings to dry for a few months I thought I'd better varnish them. Being new to the whole oil painting thing I bought a spraycan of windsor & newton satin oil varnish and applied. My problem is that the varnish seems to have sunk in or disapated or something on some areas of the painting, resulting in pics that are really patchy looking; glossy in some places and matt in others. I tried putting on another coat but the same thing happened again.
If anyone could give me any help on
1. what I'm doing wrong so I can avoid the same pitfalls next time, and
2. How to fix the paintings I've messed up
I would really appreciate it.