Cast Off

Send stains overboard. Cast Off is a professional-strength, chlorine-based stain remover that lifts mold, mildew, and organic stains from white gelcoat, fiberglass, and white marine canvas and upholstery — fast, on contact, without heavy scrubbing. It bleaches, so use it on white and light surfaces only.

Made by working detailers in the USA.

Why Chlorine

Mildew isn't dirt — it's living growth that stains deep into gelcoat pores and fabric weave. Soap lifts the surface film; chlorine breaks down the stain itself. That's why Cast Off works where other cleaners don't — and why it has to stay off colors and metal.

How to Use

Treat

1. Gear up: gloves, eye protection, and clothes you don't care about — it bleaches fabric on contact.
2. Work outdoors or with hatches open. Cast Off releases chlorine vapor.
3. Make sure the surface is cool and shaded.
4. Mask or pre-wet nearby metal fittings and anodes.
5. Spray directly onto the stain. Coat evenly.
6. Dwell 1–5 minutes — rinse as soon as the stain lifts. Never let it dry.
7. Agitate gently with a soft brush if needed.
8. Flood-rinse the area and everything nearby with fresh water.
9. While it's still wet, wash with Strip Tide, then flood-rinse again.
10. Repeat short applications on heavy stains, then re-protect.

Don't use Grease Gone on the same surface in the same session. Strip Tide is the only product to use right after Cast Off.

Safe to Use On / Do Not Use On

✅ Safe on: white gelcoat · white or light fiberglass hulls · white vinyl upholstery (test first) · white canvas covers and bimini tops (test first) · white awnings · concrete pads and docks (may lighten colored concrete) · white tile and grout · porcelain · glass (rinse promptly) · white or light plastic trim

❌ Do not use on: any colored fabric, upholstery, canvas, or carpet · aluminum, including anodized · stainless steel (extended contact pits it) · brass, bronze, and copper · galvanized metal · zinc anodes · carbon steel · polished metals · dark marble, granite, and natural stone · wood and teak · leather · vinyl wraps and decals · tinted windows · acrylic and polycarbonate · rubber seals · carbon fiber · painted brightwork

When in doubt, test in a hidden area first.

Never Mix With

Mixing Cast Off with any of these releases toxic chlorine or chloramine gas:

• Acids — Zero Spot, Reel Clean, vinegar, rust and scale removers, toilet bowl cleaners.
• Ammonia-based cleaners — including many glass cleaners.
• Grease Gone and other MAD Soaps products — Strip Tide is the only approved follow-up.
• Pool chemicals or any unlabeled cleaner.

Smell a sharp chlorine odor stronger than the product itself? Stop, ventilate, leave the area, and flood the surface with fresh water.

Pro Tips From the Field

• Spot test, every time. On canvas, vinyl, or anything not pure white: small spot, 5 minutes, rinse, inspect.
• Mask anodes and fittings with tape and plastic before working on hulls.
• Top-down on vertical surfaces. Runoff lands on areas you're about to treat anyway.
• Short hits beat long dwell. Apply, 2 minutes, rinse, repeat if needed.
• Canvas: lay it flat in the shade, keep the stain wet 2–3 minutes, then flood-rinse with a hose.
• Fresh water, not seawater. Salt water leaves deposits.
• Ventilate interiors. Open hatches and port lights; run a fan.
• Store it right. 40–90°F, out of the sun. Use within 12 months of opening — bleach weakens with heat and age.

Pairs With

• Mold Removal System — Cast Off + Strip Tide + Capt. Conditioner
• Strip Tide — the approved follow-up wash
• Canvas Juice — bleach-free option for colored canvas
• Boost Coat — re-protect gelcoat after treating

Safety & SDS

DANGER — corrosive bleach. Causes severe skin burns and eye damage. Very toxic to aquatic life — keep the concentrate and runoff out of the water and storm drains. Wear chemical-resistant gloves and splash goggles. Never mix with acids or ammonia. Keep out of reach of children. Use the Download SDS button below for full safety information.