On the issue of rebates, Cawley said: “The danger is that most oil processors simply want the oil and they don’t necessarily care about the wider service elements that most garages demand.  These include disposal of materials ranging from paint waste to tyres, with the assurance of regular collection.”

It’s a point taken up by Richard Brown, head of business development for SWR Waste Management: “Some collection companies win or lose business on rebates for oil, but garages could be losing out on battery disposal, with batteries fetching £400 a tonne. It’s like choosing a garage purely on labour rates; sure, they are important, but other considerations need to be taken into account, like competence and reliability. Workshops need to strike a balance between collection costs and rebate income and we are very transparent with our offer.”

Benfield Motor Group, with 34 dealerships representing 16 brands, uses Oakwood to collect all its waste. “The rebate for used oil is north of 10p a litre, but since the other waste is collected free of charge, I would estimate that the value of the oil is nearer 17p a litre,” said group purchasing manager David Hall.

The group uses gas for heating, but it’s considering biomass compressed wood pellets for a new-build Audi outlet.

Oil suppliers such as Castrol and Shell, along with some car manufacturers, have tie-ups with waste disposal groups, with ‘preferential rates’ for garage customers.

Castrol’s arrangement is with OSS, which uses waste to produce a processed fuel oil (PFO). It’s about 20 per cent cheaper than virgin fuel and is used across industries including industrial and process heating, glass production, dairies, brewing and food processing.

However, there is another option that sounds too good to be true. Simply retain all the waste oil, put it in a burner in your workplace and make a tidy saving in heating costs.