There's no way to prevent exposure of the drum to the clothes tumbling inside. All you can do to minimize contact with the metallic fasteners and decoration is turn the items inside-out when drying.

IN addition to that.....The inside of my Duet dryer is NOT stainless steel. It's the typical white. Every single dryer I have ever had has been white inside and stained blue from drying blue jeans and that blue stain is there for good. I've seen others dryers that are not stained and I'm thinking "why"?

For the blue stains you can remove them with a gentle scrubbing with Bon-Ami. It will remove the stains without scratching the drums surface.

Before washing your clothes make sure all buttons are buttoned and all zippers zipped up. This will help minimize their contact with the dryers drum surface.

The why of the blue dryer drum stain is because the indigo dye used on jeans isn't stable. Other than perhaps looking unsightly, the stain is harmless, doesn't rub off onto other clothes, and doesn't hurt the drum finish. I've never felt a need to try cleaning the "jeans stain" off my dryer drums.

In addition to DualRef's cleanser suggestion, I recall a dryer manual suggested a paste of powdered detergent would remove the stain.

I have the same dryer. I found that the lint builds up inside the machine. Kill the power, unplug from the wall, pull the lint screen, un-screw the screen holder, vaccum out the link. Once a month or so if you wash alot.