yes!, slightly damp cloth is best. I would be wary of any lens tissue that contains alcohol, as it might remove/damage the surface. Alcohol certainly removes the colour coating on Ilford under-lens filters! Don't ask me how I know...........
"leather" is a very generic term. Much leather these days is "colour coated" or even laminated with a "plastic" surface. The body of the fabric might even be compressed leather fibres that have previously been macerated with adhesive and is "leather" only to the extent that there is some animal protein in there (bit like cheap burgers). Coated and finished leather is designed to be waterproof up to a point and resist stains, and most "leather" restoring products won't penetrate. I have no idea what "leather" rollei originally used.