Kathy, I've not seen the aged mason jars that you described. However, I have painted on glass and ceramic before. I do use a sponge to get a "mottled" look which does give an "aged" look. I think you would be able to do that well enough. It is easy using a sponge, but always dap your sponge on a piece of paper once or twice to get excess paint off before putting it on your jar. This takes off the "glumps" of paint. Also, you can find in craft stores Preparation solution to use on glass and ceramics that help your paints adhere to the jar better. It is to clean the glass well.....it has alcohol in the solution. I have used just plain alcohol before doing my painting and got good results. I use regular acrylic decorative painting paints on my glass. There are special paints for glass and ceramics but I sometimes think they are same thing ....just trying to sell more paint! Ha! However, they might have something special in them but like I said, I use the same paints that I paint on canvas, and wood!

Enjoy your painting.