There were good reasons why the gas company promoters thought that coke sales would be profitable ‑ it already well known, particularly in industry. Both Winsor and the Chartered Company promoters gave publicity to it by listing a number of suggestions of how to use it - all of them based on current practice.
Frederick Accum described some of these practices at the 1809 Parliamentary Enquiry. He opened the proposed gas company's evidence and began at once with a submission on the use of coke and its virtues as a fuel. This coke, however, was special because it had been produced by 'Mr. Winsor's method'. Accum said that this way of making coke was 'greatly and generally superior'. He was not, however, 'permitted to disclose the process ' although he told the Enquiry that he had used 'Winsor's coke' to smelt 'lead ore, copper and iron'.
Accum went on to give a report of a demonstration which had been specially set up for the Enquiry. This coke had been tested in a blast furnace at Mr. Joseph's foundry in Lambeth'. Mr. Joseph had previously made his own coke in a stove 'open at the mouth only'. Winsor's coke making process had brought the charge time down by ten minutes, and gave more heat. The resulting iron manufactured at Lambeth 'would run through the eye of a needle'. David Walker, 'Mr. Joseph's foundryman', gave evidence to the Enquiry. He found that 'Mr. Winsor's coke ... gave more heat than my master's coke' and said that he would definitely pay more for it 'if I had the business in my own hands'.
The Chartered Company's promoters had a number of other suggestions about the use of coke. It might, for instance, be ground up as an ingredient in gunpowder. It would then substitute for charcoal bought from France - an obvious advantage since Britain and France were then at war. No more is heard of this idea but since any experiments done on such a sensitive matter would, no doubt, have been secret, the silence is not surprising. The potential of use for gas by-products in explosives may explain some of William Congreve's interest in the early industry.