As a pharmacy technician you are a leader when it comes to safe and effective compounding practice. A key component of this is ensuring that the equipment you are using is in good working order, clean and free of contaminants. By cleaning your balance after each use and in between weighing substances you will be minimizing cross-contamination risk, ensuring your safety and the safety of your co-workers and patients, and reducing equipment failure rates.
Check out this Reference Paper from Mettler Toledo: 8 Steps to a Clean Balance and 5 Solutions to Keep it Clean for a great guide to get you started. If your balance is from a different manufacturer be sure to check out the manual it came with for specific information on how best to complete cleaning and routine maintenance.