Penelope:
In my study at home (which has walnut paneling), as well on the gallery
walls at the Carnegie Arts Center (which are painted with flat paint), I
use a product called "Fun Tack." The material is produced under other
names but is basically a gum-like material which can be applied to the
back side of the label and adhered to the wall. It is reusable and
completely removable from sealed surfaces. (A similar product is used to
adhere glass, porcelain, and ceramic works to their bases.) The drawback
to the material is that it will leave an oily stain on flat wall paint
and paper.  I have seen the oil penetrate a sheet of bond paper after
about 7 to 10 days, yet it will not completely penetrate paper mounted
on board even after 4 to 6 weeks. So, I would not recommend it's use
without first testing it out on an obscure area of your paneling for at
least a few weeks to determine if it will leave a stain. I have not had
any problems using the material on the walnut paneling in my home;
however, I don't know what type of varnishes/oils were used to seal the
surfaces.

John A. Vallerga
Gallery Chairperson
Carnegie Arts Center
Turlock City Arts Commission