wet sand

Short definition from Wiktionary

Verb

1. 1
   To sand using extremely fine-grained sandpaper, using a lubricant such as water or oil to prevent the sandpaper from clogging.
2. 2
   To smooth damp material using a sponge.
3. 3
   Alternative form of wet sand: To sand with fine-grained sandpaper and lubricant.
4. 4
   Alternative form of wet sand: To smooth with a sponge.