I. Internal Scale/Water Stains (Most Common)

Scale primarily consists of calcium carbonate and magnesium carbonate formed when calcium and magnesium ions in water are heated, making it an alkaline substance.

Core Principle: Use acidic substances to dissolve scale.

Method 1: Food-Grade Citric Acid — Safe and Effective First Choice

1. Materials: Food-grade citric acid (available online or in supermarkets, safe for consumption), hot water.

2. Steps:

·Pour approximately 20-50 grams of citric acid into the thermos (adjust based on scale severity).

·Add freshly boiled hot water, ensuring it fully covers the scaled area.

·Secure the cap, gently shake, then let sit for 30 minutes to 1 hour. For thick scale, extend soaking time or increase citric acid as needed.

·Drain the solution and rinse thoroughly with clean water 1-2 times. The scale will vanish completely, leaving the bottle sparkling like new.

【Method Two: White Vinegar — Convenient Household Solution】

1. Materials: White vinegar, hot water.

2. Steps:

·Pour white vinegar into the bottle, filling about 1/5 to 1/4 of its capacity.

·Add hot water to fill the bottle completely, then screw the cap tightly.

·Let sit for 1-2 hours (soak overnight for severe buildup).

·Drain the vinegar solution and rinse thoroughly with clean water until the vinegar smell disappears.

【Method Three: Baking Soda + White Vinegar — Powerful Foaming Action】

·This method produces vigorous reaction and is best suited for spot cleaning bottle openings or as an auxiliary method. Avoid using it inside the entire thermos, as excessive pressure may build up.

·Steps: Pour a small amount of baking soda into the bottle, then add white vinegar. The mixture will produce abundant foam that effectively lifts grime. Once the reaction stops, scrub with a brush and rinse thoroughly.

II. External Stains on Thermos Bottles

1. General Stains like Dust, Grease, Fingerprints

·Method: Squeeze a small amount of toothpaste onto a soft cloth, dampen it slightly, then wipe the thermos exterior. The abrasives and surfactants in toothpaste effectively remove grime without scratching. Finish by wiping clean with a        damp cloth.

2. Stubborn Stains or Adhesive Residue (e.g., label residue)

·Method 1: Tiger Balm or Rubbing Alcohol

→ Apply Tiger Balm or medical alcohol to the adhesive residue and let it soak for a few minutes.

→ Gently wipe with a soft cloth or paper towel to easily remove the residue.

·Method 2: Hair Dryer

→ Direct the hot air setting of a hair dryer at the adhesive residue. The heat will soften and melt the adhesive.

→ While still warm, rub it off easily with a cloth or your fingers.

3. Matte/Brushed Stainless Steel Surfaces

·Caution: Avoid abrasive tools like steel wool, which may scratch the surface.

·Method: Dilute a neutral cleaner (e.g., dish soap) and wipe with a soft cloth. For stubborn fingerprints, use 75% alcohol wipes—they clean, disinfect, and evaporate quickly without leaving water marks.

III. Mold/Dirt in Bottle Openings and Crevices

These are cleaning blind spots prone to bacterial growth.

·Method 1: Baking Soda Paste

→ Mix baking soda with a small amount of water to form a paste.

→ Dip an old toothbrush or cotton swab into the paste and scrub the bottle threads and crevices thoroughly. Baking soda has mild abrasive properties and effectively removes stains and odors.

→ Rinse thoroughly with clean water after scrubbing.

·Method 2: Diluted 84 Disinfectant Solution (Only for white plastic or ceramic bottle mouths; use with caution)

→ Caution: 84 disinfectant has bleaching and corrosive properties; not suitable for metal or colored plastics.

→ Dilute 84 Disinfectant with water at a 1:10 ratio.

→ Dip a cotton swab into the diluted solution and apply it to the mold spots. Let it sit for a few minutes.

→ Once the mold spots fade, rinse thoroughly with plenty of clean water.

IV. Odor and Stains on Rubber/Silicone Seals

Seals that come into direct contact with hot water are prone to yellowing and developing odors.

·Method:

→Remove the seal (if possible).

→Soak in warm water with a small amount of baking soda or white vinegar for 15-30 minutes.

→Scrub crevices thoroughly with a toothbrush, then rinse with clean water.

→Place in a well-ventilated area to dry completely before reinstalling.

Cleaning Tips and Precautions

1. Safety First: After using any chemical cleaner (e.g., citric acid, white vinegar), thoroughly rinse with copious amounts of water to ensure no residue remains.

2. Avoid Physical Scratches: When cleaning inner and outer surfaces, never use steel wool pads, hard-bristle brushes, etc., to prevent scratching the inner coating or outer shell. This could lead to easier dirt accumulation or compromised         insulation performance.

3. Regular Cleaning: Deep clean the interior at least once monthly to prevent significant scale buildup.

4. Maintain Dryness: After cleaning, always open the lid and allow both the inner tank and outer body to air dry completely before closing and storing. This prevents bacterial growth and unpleasant odors.