Question

What happens to infrared radiation when it comes to contact wih a shiny suface

Answer 1

If a surface looks "shiny" to you, that's because it reflects all
or most of the visible light that hits it.  That doesn't always mean
that the same surface reflects other, non-visible wavelengths of
light.  Infrared radiation may also reflect off of it, and probably
does.  But you can't be sure just because it's visibly shiny.  

Answer 2

If you didn't know, some surfaces are better than others at absorbing and reflecting infrared radiation.If infrared radiation comes in contact with a shiny surface the shiny surface reflects the radiation.(shiny surfaces are the best reflectors). Hope this helps you :D