I literally just got back from washing my Lexus RX330 in the coin op wash bay. $7.50 for one hour. My trick is waiting until the temps are around freezing. Yes, you Floridians and southerners, freezing temps 27-35 in Wisconsin Januaries are warm. Our forecasted high for Sunday is -8 or low -20. Don't ask why I'm still living here. Today it was 27 degrees. Listed below is a guaranteed way to have as scratch free and salt free cars in winter as possible. Learned these tricks from YouTube watching videos from Larry @AmmoNYC, Chemical Guys and Adams.
1. Dress for the cold, jacket (I like fleece), water proof winter boots and a warm hat. Gloves are optional.
2. Very important step. Fill your two buckets with the hottest water your water heater can produce and your hands can handle. (I promise your hands will thank you as you are washing) My wife yells at me when she uses my scalding hot water as I'm washing dishes. I have a high heat pain tolerance I guess.
3. Add your wash media/shampoo of choice. I used Meguiars Gold Glass today. I like to add a little soap to the wash mitt and lay it on top of approximately 4 gallons of hot water. Don't forget the two grit guards.
4. Get a pair of water tight covers for your two five gallon buckets. And make sure they are water tight. Walmart water tight lids in their paint dept $1.77 each. Trust me you need covers. Unless your trip from to coin op is on a slot car track, you will spill water without lids. Gamma seal lids look awesome. AG sells them, probably worth the money. Walmarts lids are cheap and harder to work with. Place the buckets in an area to minimize the risk of them tipping over. I don't want to test the water proof nature of my lids
5. Once at the coin op use the rinse cycle and I start by rinsing the frame, under carriage, wheels and wheel wells.
6. Rinse the car, top to bottom. Spend a lot of time rinsing. I pay special attention to the body gaps, door jambs, bottoms of doors, seams around trim and lamp housings. Don't get too close to the car with the high pressure water. I tested my coin op pressure with my hand. At approximately 18 inches from the tip, I feel I won't damage anything on my car. Be careful pressurized water can damage your skin and eyes. And less importantly it can damage your vehicles paint, trim and seals.
Forgot this step. - washed wheels and wheel wells using Meguiars products and cheap flagged tipped wheel brush. Rinse off wheels and wells.
7. Wash using the two bucket method. If you are serious introduce a third wash bucket/wash mitt and dedicate that bucket to just the lower half/lower third of the dirtiest of the car. Make sure to rinse your wash mitts frequently in your dedicated rinse bucket. I use a method of using as little pressure as possible to wash each panel. You inevitably won't get off every bit of sand and salt when pre-rinsing. Mike Phillips talked about the 2x4 method. Two grit guards in each bucket. The more the merrier.
8. Rinse the car. Our wash has a dedicated "spot free rinse". I figure it can't hurt. I've seen the control room of our coin op and they had 4-6 water softeners so I'm guessing the water is treated.
9. Dry using soft microfiber/waffle weave towel. I used Meguiars express/quick wax as a drying aid lubricant. I dried the door jambs. And dried my weathertech mats.
45-60 mins later you have the cleanest daily driver in your town
The faster you work the warmer you get. Our coin op has garage doors and mildly heated water. That make 27 degree washing more pleasant. YMMV
** Not responsible for frozen doors, gas doors, trucks, or Windows. Dry thoroughly! **