[Can I continue to work offline with Word whilst using CCleaner drive wipe?]

Is it ok to use drive wipe  on win 7 whilst working on a word document offline?

[CCleaner Very Slow]

Is there a way to speed up the process when I am wiping the free space on my computer?  I have about 393 gigs of free space that must be wiped.  It can take 18-24 hours to finish.  Any hints or advice?  Thanks.

Ran a free space wipe and it took 23 hours,but hey, who cares,the most important thing is that the wipe was succsefull, and I got a well deserved sleep in