What is one method to improve on using funnels for oil transfer?

Storing funnels in plastic bags can help maintain cleanliness and prevent contamination. When funnels are not in use, dust, dirt, or other contaminants can settle on their surfaces, which can compromise the quality of the oil transferred during maintenance tasks. By keeping funnels securely stored in plastic bags, the risk of introducing contaminants into the oil or the equipment being serviced is significantly reduced. This practice aids in ensuring that the oil transfer process is efficient and that the lubricants remain pure, thereby protecting the machinery from potential damage caused by impurities.

The other options available would not significantly enhance the effectiveness of funnels in oil transfer. Using metal funnels might improve durability, but it does not directly address cleanliness or the risk of contamination. A multi-use funnel could be convenient, but it does not inherently resolve the contamination issue unless properly cleaned between uses. Filling funnels with more oil can lead to spillage and additional mess, which can also lead to contamination concerns. Therefore, storing funnels in plastic bags is the most effective method to ensure they remain clean and ready for safe oil transfer.