Google Rainbow. They are still around.

tenplay wrote:
When I was a child, our family had a very effective vacuum cleaner that
collected the dirt/dust in a large water reservoir. We filled the water
reservoir with clean water when we started and dumped out the thick dark
water when we were done. It was an effective way to vacuum without the
air getting dusty. I haven't seen such a vacuum cleaner in many years.
Does anyone know of such a product that is available today? Thanks.