rubber sound deadener 'sweating'

Maybe 10 years ago I put rubber sound deadener down throughout the car when doing the interior. Ignored it ever since.

I recently had to peel it out of the trunk & rear seat area to access the gas tank and the rear shocks. It has turn _nasty_ and seems to have sweated some sticky rust coloured fluid. Not doing any apparent harm to the paint/steel below, but yuck...

IS this typical?

Phil

No, its not that - the car rarely (never) sees rain. The rubber mat is degrading and oozing this gunk. It is also pretty fragile now and tore easily when peeling it up.