Degreasers

Marketing is chaotic (colors, scents, brand names) but chemically there are only 4 families. Once you know the family, you know how it works, what it’s safe on, and how to dispose of it.

TL;DR

Is it flammable / flash point < 93 °C?
├─ Yes → solvent (Family 1) → NEVER ultrasonic, hazardous waste
└─ No → water-based, check pH:
   ├─ pH < 5 → acid (Family 4) → rust only, no aluminum
   ├─ pH 6–9 → neutral surfactant (Family 3) → ✅ safe for bikes
   ├─ pH 10–12 → mild alkaline (Family 2) → OK on steel, careful on alu
   └─ pH 13+ → caustic (Family 2) → steel only, never alu/anodized

The 4 families

1. Solvent-based (petroleum / hydrocarbon)

What it is: mineral spirits, Stoddard solvent, kerosene, naphtha, “parts washer fluid,” Varsol, d-limonene (“citrus solvent”), mineral-oil-based “safety solvents.”

Property
How it works	Dissolves grease into a single liquid phase (like dissolves like)
Smell	Petroleum / mineral / sometimes orange (d-limonene)
Color	Clear / amber / yellow-green
pH	Not applicable — they’re not water-based
Best for	Heavy automotive grease, chains, bearings, parts-washer cabinets
Safe on	Metals, most plastics (test first), painted parts (gentle)
Flammable	Yes — flash points 38–60 °C typical
Ultrasonic-safe	NO — fire risk
Disposal	Hazardous waste — licensed hauler

Label red flags: “petroleum distillates,” “Stoddard solvent,” “naphtha,” “aliphatic hydrocarbons,” “flash point 38 °C,” flammable diamond symbol.

2. Water-based, alkaline (caustic / “soap-and-builder”)

What it is: Simple Green (regular), Purple Power, Krud Kutter, Zep Industrial Purple, Castrol Super Clean, Spray Nine, washing soda solutions. Sodium-hydroxide or sodium-metasilicate based.

Property
How it works	High pH saponifies grease (turns it into water-soluble soap) + surfactants emulsify the rest
Smell	Soapy, sometimes ammonia-like at high pH
Color	Purple / green / blue dye is the marketing tell — no chemical meaning
pH	10–14
Best for	Engine grime, road grime, baked-on grease, concrete oil stains
Safe on	Steel, glass, concrete
NOT safe on	Aluminum (etches/discolors), anodized parts, polished metal, paint (strips wax/clear), rubber (degrades), wood
Flammable	No
Ultrasonic-safe	Yes (dilute) — but watch alu
Disposal	Dilute & drain (check sewer-use bylaw) — usually OK at low concentration

Label red flags: “pH 12+,” “sodium hydroxide,” “sodium metasilicate,” “alkaline,” “caustic,” “highly alkaline,” “Do not use on aluminum.”

3. Water-based, neutral (pH 6–9, surfactant-only)

What it is: Simple Green Pro HD, Simple Green Crystal, “aircraft-safe” / “aluminum-safe” cleaners, Finish Line Super Bike Wash, Muc-Off Bike Cleaner, Pedro’s Pig Juice, dish soap (Dawn).

Property
How it works	Surfactants only — wrap grease droplets so they wash away with water. No saponification.
Smell	Mild / soapy / sometimes citrus fragrance
Color	Clear, blue, or pale yellow
pH	6–9
Best for	Sensitive metals (alu, anodized), painted/decal parts, regular maintenance, ultrasonic tanks
Safe on	Essentially everything — alu, anodized, paint, rubber, plastics
NOT safe on	Nothing common; just slower on heavy baked-on grease
Flammable	No
Ultrasonic-safe	Yes — bike-safe sweet spot
Disposal	Drain (within bylaw limits)

Label green flags: “pH neutral,” “aluminum-safe,” “aircraft-safe,” “non-caustic,” “Pro HD,” “Crystal.”

4. Acid-based

What it is: citric acid (organic, weak), phosphoric acid (“rust converter,” CLR), oxalic acid (wood bleach, Bar Keepers Friend), muriatic/HCl (masonry).

Property
How it works	Dissolves rust (iron oxide) and mineral scale. Does NOT remove grease.
Smell	Sharp / sour / sometimes citrus (literally, for citric acid)
Color	Clear / pale yellow
pH	1–4
Best for	Rust removal, mineral scale, dried-on inorganic deposits
Safe on	Steel, glass (rinse quickly)
NOT safe on	Aluminum, anodized parts, zinc plating, brass, concrete
Flammable	No
Ultrasonic-safe	Yes — neutralize with baking soda after, oil parts immediately
Disposal	Neutralize with baking soda → drain

Label red flags: “rust remover,” “delimer,” “scale remover,” “pH 2,” “do not use on aluminum.”

Decoding the marketing tells

Cue on label / bottle	What it usually means
Purple	Alkaline degreaser (Castrol Super Clean, Zep Purple, Purple Power) — etches alu
Green (“Simple Green” regular)	Alkaline-leaning surfactant blend — regular Simple Green etches alu; only “Pro HD” / “Crystal” variants are alu-safe
Blue	Often neutral surfactant (windshield washer, glass cleaner, mild general cleaner)
Orange / amber + citrus smell	Could be d-limonene solvent (flammable!) OR water-based with citrus fragrance added. Read the SDS — flash point < 60 °C = solvent
”Citrus” / “Citra” in name	Almost always d-limonene → technically a flammable solvent even though it smells like oranges
”Citric” in name	Citric acid → rust remover, not a degreaser
”Aircraft” / “Aluminum-safe” / “pH neutral” / “Pro HD” / “Crystal”	Family 3 — your safest bet for mixed-metal bike parts
”Industrial strength” / “Heavy duty”	Usually high pH (alkaline) — etches alu
No water listed in ingredients	Solvent-based → flammable → not ultrasonic-safe

How to identify what you’ve got in 30 seconds (read the SDS)

Every Canadian supplier must provide a Safety Data Sheet (SDS). Three sections tell you everything:

1. Section 3 — Composition: if you see “petroleum distillates,” “naphtha,” “Stoddard solvent,” “d-limonene,” “mineral spirits” → Family 1 (solvent, flammable, NOT ultrasonic).
2. Section 9 — Physical and chemical properties:
   • pH = the family decider
     • < 5 → acid (Family 4)
     • 6–9 → neutral surfactant (Family 3) ✅ bike-safe
     • 10–12 → mild alkaline (Family 2) — careful on alu
     • 13–14 → caustic (Family 2) — never on alu
     • “Not applicable” / blank → solvent (Family 1)
   • Flash point — if listed and < 93 °C, treat as flammable
3. Section 7 — Handling: any “incompatible with aluminum” / “do not use on anodized” tells you Family 2 alkaline or Family 4 acid.

Buying from Monarch Oils (or any industrial supplier)

Industrial oil/lubricant distributors (Monarch, Macewen, Petro-Canada Lubricants, Imperial Oil) typically stock:

• Parts-washer solvents (Family 1) — pail/drum size, for cabinet/sink parts washers. Don’t put in ultrasonic. Flammable. Hazardous waste.
• Aqueous parts-washer concentrates (Family 2 or 3 depending on product) — for heated aqueous parts washers and ultrasonic tanks. Often labeled “low-foam,” “aqueous,” or “ultrasonic-compatible.”
• Citrus cleaners — could be water-based (Family 3) or d-limonene (Family 1). Check the SDS Section 9 flash point to know which.
• Acid descalers / rust removers (Family 4) — for boilers, cooling systems, scale.

What to ask for

For bike work, ask:

“Aluminum-safe, low-foam, aqueous ultrasonic degreaser, pH 8–10, no d-limonene.”

That spec uniquely identifies a Family 3 product suitable for bike work. The brand doesn’t matter; the spec does.

Common ultrasonic-suitable products in industrial supply

• Elma Tec Clean A4 (German, gold standard for jewellery/precision)
• Branson EC series
• Crest Citrus (despite the name, pH 9 water-based)
• Magnus / SC Johnson Pro aqueous lines
• Petro-Canada Sentron aqueous cleaners
• Henkel Bonderite C-AK series (aluminum-safe industrial)

What we use for bikes (default recipe)

For most bike drivetrain work in our ultrasonic:

• 1 part Simple Green Pro HD : 10 parts hot water (Family 3)
• 55 °C, 8 min
• Rinse, dry, re-lube

For rust:

• 5–10% citric acid in water (Family 4)
• 50 °C, 10 min → baking-soda neutralize → rinse → oil immediately

For pre-soak / chain wax prep:

• 90%+ isopropyl alcohol in a sealed glass jar inside a water-filled tank (Family 1, but safely contained)

See Ultrasonic cleaner for full procedure.

What never to use on bikes

• Brake cleaner / carb cleaner on rubber seals, hydraulic brake parts, anodizing
• Acetone on painted/decal frames, plastics, carbon resin
• Oven cleaner / Easy-Off — strips anodizing in minutes
• Muriatic acid / HCl — destroys everything
• Gasoline / diesel as a parts cleaner — flammable, leaves residue, regulated