Streak-Free Window and Glass Cleaner with Castile Soap
A very weak Castile Soap solution and a good glass cloth are all you need for streak-free windows and mirrors.
Takes 2 minutes · Makes 250 ml
What you’ll need
- ½ tsp
- 250 ml
Distilled water or boiled water, slightly cooled
-
Measuring jug, Container/Bowl for mixing
Method
- Add ½ tsp (2.5 ml) Organic Castile Soap to 250 ml distilled water.
- Pour the mixture into a Trigger Spray Bottle using a funnel and shake gently. Make sure to label your cleaning solution with a Waterproof Label.
- Spray lightly onto a Fishscale Microfibre Glass Cloth, rather than directly onto the glass.
- Wipe the glass from top to bottom.
- Buff with a clean, dry glass cloth for a streak-free finish.
Windows, mirrors and other glass surfaces.
Glass streaks when something is left behind: too much soap or minerals from tap water. A tiny amount of soap in distilled water lifts fingerprints and grime, and the dry buff removes the rest.
The science: How oils become soap (ScienceDirect) → · Hard water and soap scum (USGS) →
Waxed floors:
Do not use Castile Soap on waxed or oiled wood floors, because it could break down the wax.
Mixing with acids:
Since Castile Soap is alkaline, you shouldn’t mix it directly with acidic substances like lemon juice, Citric Acid or vinegar. Acid will react with the soap itself and break apart the soap molecules and neutralise its effects.
Hard Water:
Whilst Castile Soap is a very reliable and mild cleaner, it can leave a residue on shiny or hard surfaces, especially when it’s used with hard water (the soap reacts with minerals from the water to form a salt). Use Castile Soap with distilled water if you live in a hard water area or cut through the leftover residue by applying an acid rinse afterwards like this Citric Acid solution: 1tsp Citric Acid in 250ml, spray onto surfaces and wipe away any residues.
Once prepared, this spray will last for approximately 4 to 8 weeks. For optimal shelf life, store it properly labeled in amber or dark bottles to protect it from light. If it starts to look or smell off before the 8-week mark, discard it and make a fresh batch.
Store Castile Soap sealed tightly, in a cool, dry place, away from direct sunlight.
Our fragrance-free Organic Castile Soap is hypoallergenic, pet- and skin-safe, which means it’s less likely to cause allergic reactions than other types of soap. Needs dilution: If you don’t dilute Castile Soap with water, it can be very concentrated. This can make it hard on surfaces and the skin.
B&M Pro-Tip 1:
Less is more when cleaning glass. Too much cleaning solution can leave residue and cause streaks. Distilled water helps prevent mineral marks, while spraying onto the cloth rather than directly onto the glass prevents excess solution from running down the surface. Avoid cleaning in direct sunshine or when the glass is hot, as the solution can evaporate too quickly and leave streaks.
Dry the glass completely with a Microfibre Glass Cloth before the water evaporates. Any liquid left on the glass can cause streaks. Use a fresh, dry Microfibre Glass Cloth and wipe in long, straight motions from top to bottom. Fold the cloth a few times to create multiple dry sections. Continue wiping from edge to edge until the cloth has absorbed all the remaining water. If you are left with a streak or two, just give it a swift buff, and you’ll have it looking perfect in no time!
B&M Pro-Tip 2:
Use lukewarm, not hot water, and pick a cloudy day: sun and heat dry the solution before you can buff, which leaves streaks. Never pour hot water on cold glass. Hot or cold water? →
Quick questions
Why do my windows still streak?
Usually too much solution or cleaning in sunshine. Spray the cloth, not the glass, and buff dry straight away.
Can I add vinegar?
No. Vinegar curdles Castile Soap. If you want an acid rinse, use our Citric Acid spray separately.
Try this next: Microfibre Cloths →
