Pre-Soak, Prep & Wheel Cleaning: the full procedure

Apply pre-soak and hand-prep heavy soil, bugs, and wheels before the vehicle reaches the main wash so the finish comes out clean in one pass.

• Applies to: Prep attendants, tunnel loaders
• Frequency: Every vehicle (prep stage)
• Scope: Covers the manual prep sequence that removes heavy soil and dresses wheels before the main wash. All chemical selection, dilution, and contact time DEFER to the product label/SDS; spray-overspray to drains defers to EPA water-discharge rules and the business safety plan.

What you need

• Pre-soak applicator/wand
• Soft prep brush or bug mitt
• Wheel/tire brush
• Designated chemical bottles (pre-labeled per SDS)
• Nitrile gloves and eye protection
• Dilution chart posted by the owner

The procedure, step by step

1. Confirm the right product and dilution — Use only the bottle labeled for the task; verify dilution and contact time against the posted chart and the product label/SDS — never eyeball or mix.
2. Put on required PPE — Wear gloves and eye protection specified on the SDS before handling any prep chemical.
3. Pre-soak the vehicle front-to-back — Apply pre-soak evenly over the hood, front bumper, and high-bug zones first, then sides and rear, keeping a consistent pattern car to car.
4. Agitate heavy soil only as needed — Use the soft prep brush or bug mitt on stuck-on soil, bugs, and lower panels; keep one mitt for body and a separate brush for wheels to avoid cross-contamination.
5. Clean wheels and tires — Apply wheel product per label, agitate the tire and wheel face with the dedicated brush, and rinse before the body brush touches the vehicle.
6. Respect dwell time, do not let product dry — Keep product wet on the surface for its labeled dwell window; re-wet if it begins to dry to prevent streaking or etching.
7. Hand off to the conveyor or main wash — Signal the vehicle forward only after prep is complete and the body is uniformly wetted.

Quality check before you finish

• Correct labeled bottle and posted dilution used every car
• Required PPE worn for the full prep stage
• Bug and high-soil zones agitated before the main wash
• Separate tools used for body vs. wheels (no cross-contamination)
• Product kept wet through its labeled dwell time
• Wheels and tires cleaned before body brush contact
• No product allowed to dry on paint or glass

This is a free, source-anchored standard operating procedure (SOP) you can print and hand to staff. It documents the work sequence for a Car Wash business — not safety or regulatory rulings, which defer to the cited authorities, the applicable code, and your own health-and-safety plan. Open the tool above to print it, toggle ink-saver, or (with a free ToolFluency Business account) edit it to match your own workflow.

Sources

• International Carwash Association (https://www.carwash.org)
• Professional Carwashing & Detailing (https://www.carwash.com)
• Chemical manufacturer label/SDS guidance (https://www.osha.gov/chemical-hazards)