This expression means to prepare for a fresh start, to have another chance after wiping out old offenses or debts. It alludes to the slate boards as a writing surface on which one could record scores in games or depts in a shop in easily wiped-off chalk. One can 'wipe the slate clean' either by paying off debts or by expunging the score of the previous game to make room for the next. Since about 1850 the phrase has been used figuratively.

Übersetzung:

die Dinge ungeschehen machen, reinen Tisch machen

Gegenteil(e)

The opposite of "to wipe the slate clean" is "to sweep something under the carpet".

Synonym(e):

You could also say: an opportunity to start over without prejudice.