Thomas L. Jennings: Inventor of Dry Cleaning, Dry Scouring, and the Evolution to Wet Cleaning

Thomas L. Jennings: Biography and Invention

Thomas Jennings was born free in New York City and trained as a tailor. Seeking a better way to clean fabrics, he invented dry scouring. In 1821, at age 29, he secured a U.S. patent for this process. (This made him likely the first Black person in America to receive a patent.) The term “dry scouring” described cleaning clothes with a solvent instead of water. Contemporary accounts note Jennings’ achievement; for example, the Smithsonian reports that Jennings’ process “would lead to today’s dry cleaning” ¹. Unfortunately, the original patent documents were destroyed in the 1836 Patent Office fire, so details of his method are lost, but its impact is clear: it enabled safer, more effective cleaning of delicate fabrics without soaking them.

Jennings used his patent profits to support abolition and education. His legacy is honored today: as Smithsonian Magazine observes, next time you visit a dry cleaner you are benefiting from Jennings’s pioneering invention.

Technological Advances Since Jennings

Since the 1820s, dry cleaning has evolved through several major solvent and process innovations:

• Perchloroethylene (Perc): Introduced in the 1930s, perchloroethylene (C₂Cl₄) became the dominant dry-cleaning solvent by the 1940s. It dissolves oils and waxes that water cannot, and is nonflammable. By the late 20th century, most U.S. dry cleaners (around 60–70%) were using perc. It’s prized for fast, deep cleaning, but must be carefully managed due to toxicity and environmental regulations.
• Hydrocarbon solvents: These petroleum-based liquids (e.g. DF-2000, EcoSolv) emerged as alternatives in the late 20th century. Hydrocarbons are milder and softer on fabrics, but they are flammable. Roughly 20–25% of cleaners now use hydrocarbon solvents. They work slower than perc and require longer drying, but can be preferable for certain delicate fabrics.
• Professional Wetcleaning: Developed in the late 1990s and 2000s, wetcleaning uses water plus specialized, biodegradable detergents and machine controls to clean “dry clean only” garments. Unlike home washing, wetcleaning is done in computer-controlled machines with precise temperature, water, and mechanical action settings. According to the Drycleaning & Laundry Institute (DLI)², it’s “the professional process of removing soils from garments… through the use of water” using special technology to protect sensitive textiles. Wetcleaning avoids solvents entirely, making it an eco-friendly option for many modern cleaners.

Many people ask:

• What is wetcleaning?

• What is professional wetcleaning?

• Is wet cleaning the same as washing clothes?

The short answer: No. Professional wet cleaning is not the same as home laundry.

It is a controlled cleaning system used by trained cleaners as an alternative to traditional dry cleaning solvents.

What Is Wetcleaning?

Wetcleaning uses water as the primary cleaning agent instead of chemical solvents like perchloroethylene (perc) or hydrocarbons.

However, it is not standard washing.

Professional wet cleaning uses:

• Computer-controlled washing machines

• Specialized detergents

• Strict temperature control

• Reduced mechanical agitation

• Controlled moisture levels during drying

• Professional finishing equipment

The goal is to safely clean garments labeled “dry clean only” using water without causing shrinkage, distortion, or damage.

What Is Professional Wetcleaning?

Professional wetcleaning refers specifically to:

A commercial, technology-driven process performed by trained cleaners using programmable equipment and fabric-specific settings.

It differs from home washing because:

• Cycles are programmed for delicate fibers like wool and silk

• Water temperature is tightly controlled

• Agitation is minimized

• Drying is carefully monitored

• Garments are reshaped and professionally finished

It is a textile management system — not just a wash cycle.

Wetcleaning vs. Solvent Drycleaning

Drycleaning and wetcleaning handle stains differently. Drycleaning uses a solvent (traditionally perc or hydrocarbon) instead of water. The solvent penetrates fabrics and dissolves grease and oils, then is filtered out, and the clothes are dried. It’s called “dry” because very little water is involved. In contrast, wetcleaning uses water like a normal wash, but with lower heat, milder chemicals, and slower cycles to protect fine fabrics. Wetcleaning excels at removing water-soluble stains (e.g. soda, perspiration) and has no solvent odor or chemical residue. Many professionals now decide case-by-case: oil-heavy stains usually go to solvent machines, while other stains or sensitive items may go to wetcleaning.

Pros & Cons: Perc vs. Hydrocarbon vs. Wetcleaning

Each method has trade-offs. Perc machines offer powerful cleaning but need careful handling. Hydrocarbons are gentler but require more processing time. Wetcleaning avoids solvents but demands precision.

FAQ: Dry Cleaning & Odors

• Q: Why doesn’t dry cleaning always remove odors? Dry cleaning targets oils and some stains, but odors (like smoke or mildew) may bind to fabrics and pads. Solvents may not extract the odor molecules, so special treatments (oxidizers or ozone) are needed to neutralize smells. Always tell your cleaner about any odors so they can use the right process.
• Q: What came before perc and hydrocarbons? Early cleaners used petroleum distillates (like Stoddard solvent) or even kerosene, which were flammable. In the late 1800s and early 1900s, those were replaced by less flammable liquids. Perc’s introduction (in the 1930s) provided a safer, more powerful solvent, so it became the industry standard for decades.

Glossary

• Dry Scouring: 19th-century term for cleaning clothes with a solvent (no water). Jennings’s invention of this process led to modern dry cleaning.
• Perc (Perchloroethylene): A chlorine-based solvent used in 60–70% of dry cleaning. It dissolves oils effectively but is toxic and regulated.
• Hydrocarbon Solvent: Petroleum-derived cleaning fluid (e.g. DF-2000). Less aggressive than perc, flammable, and requires longer dry times.
• Professional Wetcleaning: A water-based cleaning system using specialized machines and detergents for items normally dry-cleaned. Eco-friendly alternative to solvents.
• Stoddard Solvent: An old petroleum distillate (similar to kerosene) once used in dry cleaning. Highly flammable and now mostly phased out.
• AATCC: American Assn. of Textile Chemists & Colorists. They set standards (including for professional wetcleaning) that cleaners follow to ensure safe textile care.

When you bring your clothes in for cleaning, always mention any tough stains or odors upfront. That lets the dry cleaner choose the best treatment (spotting, solvent type, or wetcleaning) to remove what home laundering can’t.