Hi, I made some experiments last two days, take a look :)
http://www.sashe.sk/farbi/journal/akvarelove-skvrny-a-struktury.-trocha-farebnych-nahod-do-nasho-sed...It's in slovak language (sorry), but the photos are most important :)
I added alcohol, acetone, sea salt and table salt into the wet watercolor paintings to make these beautiful blotches and structures.
(Thank you for sharing)
Have a nice day! :)
Mya