"I am familiar with this an Schedules C's but these clients only have Schedule E's"

Are you asking about Itemizing (1040 Sched A), or about related vehicle expense for business use of a personal vehicle?

Are you also trying to use Mileage Allowance for their trips? You cannot take both Mileage, and also the Actuals that are a component in the mileage rate (operating costs, registration, insurance, etc).