Thanks guys,
I do have a polarizing lens, and will try it out. The black cloth is along the same lines as my own thoughts, and I have a 50ft roll of 5ft wide black cloth, so no shortage there. I'll give it a try.
I will try to diffuse my lights a little more, (which are just regular flood lights). In this image they were pointing directly into the ceiling (dark wood), so I was surprised by the hot spots on the top part of the vase.
Thanks for your hints,
- Thomas