Lubricant, cleaner or penetrant? Stop asking one can to do every job.

Name the problem, rather than the familiar brand

Write down what the product needs to achieve and what it will touch. Is the aim to remove grease, loosen corrosion, displace moisture or maintain a moving assembly? Also note whether a residue is acceptable. A short functional description helps you compare the right products and avoids collecting several cans that all do roughly the same thing while the actual requirement remains uncovered.

Understand the limits of a general-purpose spray

WD-40’s UK guidance says its Multi-Use Product provides light lubrication; it also notes that longer-lasting or heavy-duty lubrication may call for a specialist product. That is a useful example of why ‘lubricant’ is not a complete specification. The company distinguishes Multi-Use Product from a contact cleaner and from a degreaser. Read those distinctions before deciding what belongs on your shelf.

Check surfaces and instructions before price

Look for suitability for the exact metals, plastics, rubber, paint or coatings involved. Where the manufacturer calls for a small-area compatibility test, follow that advice. Never assume that a product advertised for electrical cleaning makes live work safe. Do not use a general workshop product as an improvised brake, food-contact or other specialist lubricant without the relevant manufacturer’s approval.

Think about where you will keep and use it

Read the label and safety data sheet for handling, ventilation, fire precautions and storage. Aerosol packaging is not a trivial detail: WD-40 classifies its Multi-Use aerosol as extremely flammable. Follow product-specific requirements and keep instructions available. Do not mix cleaning chemicals or transfer them into an unlabelled bottle to save shelf space. Select the least complicated suitable product, not the most impressive list of claims.

Compare quantity you can actually use

A larger can can have a lower cost per 100 ml, but may still be a poor purchase if you need only a small amount. Compare the same formulation and packaging format, including the applicator and delivery charge. Keep the product name and any useful batch information with your project notes. For machine lubrication, the equipment manufacturer’s specified product or performance requirement takes priority over a generic shopping recommendation.

Quick comparison

Your pre-purchase check

• Function identified
• Materials checked
• Label and data sheet available
• Storage and applicator suitable