The photo below shows erosion damage on one of the lips (step up on "Spicy").
This form of damage is caused by water collecting on various surfaces, and running down the lip surface. This is avoidable, and whenever it is observed the following steps should be taken.
Identify possible water collection zones. In this case, water could be collecting on the back of the lander, on the tops of this and adjacent lips, and potentially on lander faces.
Identify where original drainage has become compromised. During construction, all lips were checked to ensure that water flow would not run over onto the jump face.
Reinstate drainage. This will usually involve removal of sediment which case caused a blockage (as shown here). In some cases, the top of the lip will need to be subtly sloped backward thereby to encourage water flow away from the lip edge.
Repair face using appropriate repair techniques. Where ruts are significant, this can be achieved using a repeated cycle of watering and application of slightly damp sediment, for instance as part of a conventional grey dirt surface repair process.
As always: (i) take your time; (ii) finish what you start; and (iii) have pride in your work. The goal always to strive for the original as-built condition, never to modify or change. Preparation is always key, along with ensuring you have the time and patience to see a job through to the end. Quick fixes never last.