DIY Mason Jar Cupcake Favor

My girls went to a party this weekend and this was in their goodie bag.  Looking at it, I was wondering if there was some way to make it.  With a little searching online, I actually found a pictorial at Wedding Day Pins here.  And what did they use as the frosting on the cupcake?  Caulk!  A cute favor for any occasion.  Fill it with candy or bath salts.