Just to qualify what I wrote above, I think it would be reasonable to pay for actual demonstrated costs such as fuel for the mower on production of the receipt but no more. The labour component can be rewarded with thanks and public acknowledgement. Often the owner of premises has responsibility for the nature strip, so it could be a legitimate expense for the OC. Similarly, someone who replaces blown light bulbs on the common property should be reimbursed for the cost of the light bulbs on production of a receipt. Paying more than that is just likely to cause resentment among others who also contribute time but don’t get paid anything.