Is it better to leave lacerations open or covered ?

Depends: Covered if bleeding or weeping, uncovered if scabbed over and don't need to protect them is the general rule. If in doubt a virtual or inperson consult is a good idea

Clean and cover: The laceration should be washed out, cleaned and covered immediately to avoid the would getting infected.

Depends: On location and size but in general should be cleaned and covered