This 18 count package of liquid chalk makers by Stardom Crafts are water based. They are for use on plastic, glass, metal, LED boards, glossy boards, and non-porous surfaces.
They worked great for me on plastic! I had the most success with using them on plastic report covers. Since I am not gifted at drawing I thought I would trace some items, kind of like stenciling. When I traced on napkin covers the markers were not as chalky to me as they were on the plastic report covers, but were more watery. I also colored a white contact lens case so I can tell which is the left and right eyes for my contact lenses (I colored each lid two different colors). One of the colors was not as chalky as the other but I still think that project turned out great! When I traced a picture on a report cover I noticed that about 1/4 of the markers lost their chalkiness. Those came out more watery than chalky.
One of the great things about these markers is that if you mess up you can wipe away your mistakes whether they are wet or dry (I could on the plastic I used anyway). They are also non-toxic. To me they are like dry erase markers for artists and I believe they are also great for teachers!
My Review= 4.5 out of 5 stars
I received this product free in exchange for an honest and unbiased review.