To begin something anew, without being hindered by past mistakes, problems or biases; to start all over again.
start with a clean slate
Synonym of start with a clean sheet.
start with a clean sheet of paper
start over
to begin again; to return to the beginning
wipe the slate clean
To make a fresh start, for example by forgetting about previous differ …
bust the dust
To clean dust off something, such as with a vacuum cleaner.
make a clean breast
Often followed by of: to be honest about something; to confess.