Using Citra-solv with National Geographic pages is a great technique for making collage papers. Paint Citra-solv to one side only of a National Geographic double-page spread, place the "wet" side face down on the the other page & rub the back a little. Use a heat gun to dry the back of the wet page and pages are ready in a minute or so. Peel the pages apart before they stick.
In the UK Citra-solv can be bought online from 21st Century Health - I get the large 32oz bottle, expensive but works out more economical in the long run.
National Geographic pages work the best because of the ink that is used in the printing process - possibly a base of gold?