How do I clean built up grease off of my kitchen cupboards?

Tracy...Vinegar and water should help

This tip with before and after photos suggests lemon soft scrub https://www.hometalk.com/1329752/how-to-easily-remove-grease-build-up-from-your-cabinets

Here is another tutorial with a DIY recipe https://www.hometalk.com/33057663/remove-grease-from-kitchen-cabinets

Simple Green degreaser. I used it in my restaurant and I use it it my home now. I even use it on grease or oil on clothes and then pitch them in the washer as usual. The stuff is phenomenal. I love it. Try it.

I'm 71 yrs old and still and will always use my mother's favorite cleaner Mr. Clean. It is a good all round cleaner and a very good degreaser. Use it full strength from the bottle, pour it in a container w/ water or do as I do, use it diluted in a spray bottle most of the time. It comes in many colors but it's all the same thing. If the grease is really bad I would see how full strength works in a small spot and go from there. Maybe it doesn't need to be that strong. Or, go from diluted to see how strong it needs to be. Try it, you'll like it. Merry Christmas. ;-)