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Rinsing cloths used with chromate treatments

Aviation Mechanic General (AMG) practice question 24 of 31 on Cleaning and Corrosion Control. ACS element AM.I.G.R5 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONAfter field treatment of corroded aluminum with an activated chromate acid mixture, why must the sponges or cloths used be thoroughly rinsed?

  1. ATo avoid a possible fire hazard after they dry
  2. BTo recover the unused chromate solution for reuse
  3. CTo prevent the cloths from staining other aluminum parts
Show the answer and explanation

Correct answer: A. To avoid a possible fire hazard after they dry

  • A — correct The handbook directs that sponges or cloths used with commercial activated chromate acid mixtures be thoroughly rinsed to avoid a possible fire hazard after drying; chromium trioxide is a powerful oxidizing agent.
  • B — incorrect The handbook gives fire prevention, not recovery of the chemical, as the reason for rinsing.
  • C — incorrect Staining of other parts is not the hazard cited; the concern is that dried chromate residue creates a fire hazard.

BACKGROUND

Several commercial activated chromate acid mixtures are available under Specification MIL-C-5541 for field treatment of damaged or corroded aluminum surfaces. Sponges or cloths used with them must be thoroughly rinsed to avoid a possible fire hazard after drying. The same chapter notes that chromium trioxide flake is a powerful oxidizing agent and a fairly strong acid that must be stored away from organic solvents and other combustibles, and that wiping cloths used for chromic acid pickup are either thoroughly rinsed or disposed of. Stripped paint residue likewise must be disposed of in accordance with environmental laws.

STUDY TIP

When a question involves used rags, cloths, or residue from a treatment chemical, think about what the chemical does when it dries and concentrates.

KEY POINTS

  • Cloths used with chromate mixtures are rinsed to prevent a fire hazard when dry
  • Chromium trioxide is a strong oxidizer; store it away from combustibles
  • Stripped paint residue is disposed of per environmental laws

SOURCES

  • FAA-H-8083-30B ch08 "Chemical Surface Treatments"
  • FAA-H-8083-30B ch08 "Chromic Acid Inhibitor"
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.