How To Remove 2+ Year Old Vegetable Oil From Concrete?

Hi all! My name is Craig this is my first post as I’ve been able to get my business rolling just by reading and from the help of just one of the members here. LOVE this site!!! You know who you are and I can’t thank you enough! Ok, I’ve got some vegetable oil stains on an apartment complex that I’m bidding the breezeways. I did one for free… One, to gain the experience and two, too show them our professional workmanship. That being said, the management was tickled however, I was not. I do not have hot water on my machine and I really don’t think that is going to make a difference since the stains are so old. Could some of you take a look at the pic below and give me your thoughts. BTW I soft washed the breezeway so keep in mind my chems were on the concrete as I surface cleaned. Before cleaning it is a dark black stain. After cleaning leaves this dark brown stain. Any ideas or solutions to this problem would be greatly appreciated!!

Rent a hot water machine. Oil stains is when heat really makes a difference. A 3 hour rental on my area is just over $100. Easy to work into the bid. For chems I would say EBC.

EBC for sure

Thank You VERY much!

I can’t see surface cleaner marks. How did you wash the concrete?