Why do the friends prefer methylated spirit to paraffine oil?

The men had tried parraffine oil once and found that it permeated the air around then. Everything smelled like oil, and the odor of the oil followed them wherever they went. 

"We had taken up an oil-stove once, but “never again.” It had been like living in an oil-shop that week. It oozed. I never saw such a thing as paraffine oil is to ooze."

"We tried to get away from it at Marlow. We left the boat by the bridge, and took a walk through the town to escape it, but it followed us. The whole town was full of oil. We passed through the church-yard, and it seemed as if the people had been buried in oil. The High Street stunk of oil; we wondered how people could live in it. And we walked miles upon miles out Birmingham way; but it was no use, the country was steeped in oil."

"Therefore, in the present instance, we confined ourselves to methylated spirit. Even that is bad enough. You get methylated pie and methylated cake. But methylated spirit is more wholesome when taken into the system in large quantities than paraffine oil."