My kids were in charge of the Rainbow, but they

Your Rainbow might have been damaged. It would be advisable to take the machine to a shop and have them do a cleaning on it. The water is the filter, and there is a separator between the water and the motor. The separator only prevents the water from entering the motor. The dirt that goes in the water is no longer airbourne, so it cannot enter. Without water, the dirt is still airbourne and some of it could have entered. I am sure that most of what was picked up landed in the basin. Is the separator(the little nut on the bottom of cleaner holds this in) full of fluff? Take off the separator nut(there should be a wrench/toothbrush tucked in under the cleaner that is used to remove separator and clean it.) Is there fluff visible up in the machine? If so, definitely take it to a shop. The separator must be cleaned after every use. Never store water in the basin. Those are the 2 main rules for care and use of your Rainbow. Well, good luck with your Rainbow. They are truly great vacuums. Let me know if this helped you. Thanks Rene(the VAcuum Doctor)