Now, the stock levels in many shops are a mess. The reality is that the world is moving on and you need your stock right e.g. summer clothes in winter do not sell well.
This needs to be addressed.
I suggest that you look at a report that contains the sales of the stock items and the stock on hand figure. Here is one such report, the top N stock report which you can find in register reports here.
Put in the last two months and ten million-selling lines to include everything.
Now you will get a report, that has current sales figures and stock on hand.
Now you need to review these items ASAP