All colour can be printed – but what you’ll get after sticking it to something is another thing entirely.
Even putting it onto a white surface will result in a different result than printing onto white media as clear material isn’t quite optically clear and the saturation level is different.
The inks are translucent so totally useless for using on a coloured background as they will pick up the background colour in the ‘mix’.
If you have some clear – try printing something like a Pantone or RAL chart.