To add to John Rennie's answer and Noldor130884's answer: a half wavelength waveplate will reverse the handedness of circularly polarized light. It's the same principle as converting linear to circularly polarized light although here you don't have the precise alignment problems (to convert linear to circularly polarized, you need to align the input light's plane of polarization at an angle of 45 degrees relative to the extraordinary/ ordinary axes of the birefringent crystal).
An interesting aside is that, through conservation of angular momentum, the light exerts a torque on the waveplate as it does this (the classic 1936 Beth experiment actually measured this).
A disadvantage of waveplates is that they are wavelength sensitive: the aimed-for conversion is set by the thickness of the plate in waves at the particular waveplate in question. So a quarter wave waveplate at 700nm will be a half wave waveplate at 350nm wavelength.
Quartz is the commonest material that will do this and halfwave waveplates are very thin - less than a millimeter in thickness. You can probably find an optically active polymer to do this. Waveplates are expensive because not many of them are made. If a consumer electronics application with a large market for waveplates were found, you can guarantee that the same waveplates would shrink radically in cost as companies engineered ways to cheaply mass produce the item in question.
. Richard A. Beth, "Mechanical Detection and Measurement of the Angular Momentum of Light", Phys. Rev., 50, #2, pp115-125 1936