It's hard to do them deliberately, but at some point I did use dark instant coffee mixture only for the purpose of spilling and making spots. Hard to control them but the idea was for all to be abstract, so I didn't need control. At the start of it all I just turned my empty coffee cup upside down on 10 or 15 sheets of paper and left the remains of the coffee to go on all the sheets. Then I scanned them. Crazy process:)