How to remove rust stains from concrete without having to paint it?

Try pouring lemon juice or vinegar on the rust and leave on for awhile then use a scrub brush.

These Hometalkers got really helpful answers that can help you out as well: http://www.hometalk.com/diy/clean/outdoor/q-how-to-remove-rust-stains-on-concrete-pad-9549408?expand_all_questions=1 and http://www.hometalk.com/diy/clean/outdoor/q-how-do-i-remove-rust-stains-from-concrete-patio-1639509

Thank you Janet. We will try that as soon as this northeaster passes.

Thank you Hillela!

WD-40 ***** Just spray it with a generous amount of WD-40 and then hose it down with water. ***** Soda (Coca Cola) ***** Work the cola in with a bristle broom, and leave the cola for about twenty minutes. Mix 1/4 cup laundry detergent with 1/4 cup bleach in 1 gallon (3.7 liters) warm water and use it to mop up the mess. ***** Oven Cleaner ***** Spray them with Easy Off No Fume Oven Cleaner in the BLUE can. Let it settle for 5-10 minutes, then scrub with a stiff brush and rinse it off with your garden hose at its highest pressure. Severe stains may require a second application. ***** Kool-Aid ***** Nasty rust stains on your concrete? Mix unsweetened lemonade Kool-Aid with hot water. Scrub and the rust stain should come right out. ***** Ammonia ***** Tired of those annoying discolorations on your concrete work? To get rid of them, scrub with 1 cup ammonia diluted in 1 gallon (3.7 liters) water. Hose it down well when you’re done.

Thanks William!

I bought a product called Iron Out. Works like a charm on toilets so you might try it.

used wd40 on oil and it made it worse. Vinegar did not work at all

Coke sometimes works. But a commercial product to remove rust would be best.