Hello.  What is the best way to remove dust and clean textured shells that have been on display for years?  Thank you.  Brett

They can be washed in warm water with a little dish detergent, using a small soft brush.  But the very best way to clean down into every tiny crevice of a highly textured shell is an ultrasonic cleaner.  I have two of them and it's amazing how much dirt and dust they can remove, even from a shell that has already been washed.  They are also great for cleaning operculums.