You must know your stock levels. Top up exactly what the prize meter says you should on collections during the month. For the last collection of the month, physically count and top up to what is required. Differences will pick up:

• Errors made during the month
• Suspicious activity on location
• Double pickup of toys registering as one on sensor
• Prize sensor faults

Don't physically count every time - it's a waste of time.

When you pull all prizes out at end of month, use the opportunity to do an End of Month Spring Clean.