Mysql Slow Log is Large - Can it be reset?

Hi

I have a slow.log located here:

var/lib/mysql/server1-slow.log

It is 14G which is massive.

I did a SET GLOBAL expire_logs_days =5;

Tried to do a purge
PURGE BINARY LOGS BEFORE (date(now())+ interval 0 second - interval 5 day);

but the var/lib/mysql/server1-slow.log is still there.

Can I simply delete the server1-slow.log file in WinSCP and then restart mysql to have the file regenerated factoring in the expire_log_days new setting?

Thanks