The oil fills small surface cracks that may otherwise harbor bacteria.

Those cracks may not go all the way through the mud; they're "surface cracks."

I am unable to do justice to the surface cracks that it is covered with.

I reached for one of the rolls, felt the thin, butter-glazed surface crack under my light pressure.

This not only serves to initiate surface cracks but (see below) actually modifies the crack growth process.

Thermal fatigue is when surface cracks occur on the die due to a large number of cycles.

Over time, water seeped into the surface cracks, joints, and folds of these layers.

One hose seemed to have a surface crack but he couldn't spot a leak.

The physical effects of spot welding include internal cracking, surface cracks and a bad appearance.

"A form of lichen that protects itself from the wind by living inside the surface cracks."