If the grain store delivers three kinds of grains: rice, wheat and corn, here are some suggestions:

1. Classified storage: Store these three kinds of grain in different storerooms or storage containers to avoid cross-contamination.

2. Check the quality: Check the quality of each granule. If there are any bad granules or impurities, you need to pick them out.

3. Quantity statistics: Count the quantity of each grain, which is convenient for calculating the sales volume and inventory.

4. Pricing sales: consider pricing according to market conditions and costs, and decide how to sell these grains.

Please note that if you are engaged in food business, you need to abide by relevant laws and regulations to ensure food quality and safety. At the same time, according to market demand, we should rationally arrange supply and marketing strategies to ensure food supply and quality.