We moved over to envelope and cheque payments being sent about 15 months ago now. Everythings fine with this.
Because of this I decided to extend our 'Today your windows were cleaned' leaflet that gets left with the envelope.
It basically reads like this;
Today (date) your windows were cleaned. The price is £.........
Can all cheque payments be made within seven days of the clean.
On the bottom I have added 3 extras;
Today our windows were cleaned and there was a problem - it was (and then space for them to let us know)
We would like you to give us a price on the following work (space for them to let us know - we offer multiple services)
Our friends would like their windows cleaned - their name & address with phone number is (space for details). (On this the person recommending gets a 50% reduction on their next clean if we get the new clean)
We get work from this approach regularly and pick up 4 or 5 new cleans per month with it as well as additional work we wouldn't normally get.
It works for us - it might work for those looking for extra work
Good luck
Rob