Need some help with rust removal pricing

Hello all,

I need some guidance on adding pricing to a job for rust removal. The customer wants me to provide a quote for pressure cleaning a 1500sqft driveway that also has rust stains around the edges from a sprinkler system. The customer knows that pressure cleaning alone will only remove the black mildew and dirt (yes I use SH) but not the rust. My question is what would be the best and most profitable way for me to charge for the rust removal? I’m paying about $19.50 per gallon for rust destroyer and don’t have an idea at this point how much I will use. I can’t imagine it would be more than 5 gallons.

All wisdom is appreciated greatly. “Use the search box”, not so much.

pic would help