Do you suggest washing (soap & water) the Verlinden bldgs. before starting any painting or priming?

I'd suggest not to and stay away from putting water on it. It's a dried plaster and water is going to destroy it. I've always just primed it first.

if the building is made from plaster then no, as James said there is no need but if they are made from resin then yes clean them with soapy water before priming them.

Thank you both. I think i messed up. I hope it dries in a couple of days.