i have to say clifford, that i too scoffed at the oven cleaning business about 18 monthas ago, until i bumpwed into a chap on an end of tenancy clean. He proceeded to explain to me that he was earning about a grand per week.......................per van, average job around about £50 and doing 4 cleans a day, he has two vans on the road. he cleans himself, and pays other lad £300 per week.
So it can be done, i have witnesed it first hand, as for marketing with leaflets, you need to look at the bigger picture, this guy covers an area that is about 60 - 70 mile round and advertising in all local rags, also leafleting, radio failed to make money, and 6 monthly direct mail shots to exisiting customers................although he may be taking a grand a week per van, what is he actually putting on the table? if i were in your shoes i would run some dummy ads, flyers etc and then see what response you got, then maybe work out your potential earnings from this.
I have crossrefrenced the infomation i was told with, the chap in shropshire oven master, and "the oven cleaning compnay in surrey, i think it is a viable business, but dont be under any illusions that you will make a business just out of leaflets alone. Making a business will be down to your expertise in marketing.