"False-backs" are caused by abrasion of the grain during liming, when the hides are in a swollen condition. TFL advises on the conditions in the drum, and the use of suitable auxiliaries to control the swelling.
Scuff marks or abrasions of the grain are usually caused by rough areas in the vessel, particularly drums, or by simply too much or too fast running after the grain has become swollen. Running, once the hair has been removed, should be kept to a minimum and vessels should be regularly checked for sharp edges, rough areas, exposed bolt heads etc.
On sensitive raw material prone to scuffing from normal running add a suitable slip agent ERHA GM 3034 / 3995 after the hair is removed and before any real swelling commences.
Good Practice: Check vessels once a week for conditions likely to cause scuff or cuts.