Active Oxygen Descaling Tablets

Well, I was so into cleaning videos lately and came across this active oxygen thingy. So when I found this "Active Oxygen Descaling Bubble Water Cup Tea Scale Removal Kettle Scale Removal Cleaning Tea Set Tea Cup Cleaning Effervescent Tablets" in Lazada, I bought it, it's cheap (I think), it's around RM1 one box (10 tablets per box). So a tablet cost around 10 cents.

Well, on the packaging, there's printed sentence "high efficiency bubbling tablets". Well, when I opened it, only 1 tablet that still somehow maintain the tablet shape, others all became powder already. I read the ingredients list, it has baking soda 小苏打, citric acid 柠檬酸,  active oxygen agent 活氧因子, cleaning agent 去垢因子(not sure actual is what chemical, just literal translate). The list sounds not dangerous, so although it has becomes powdery, I used it nevertheless. 

active oxygen descaling bubbling happiness

only 1 left that somehow maintain the tablet shape

one month before expiry!

Anyway, I kept 3 coffee / tea stained cups and intended to use this tablets on my stained cups. Actually I could still clean it with good hard scrubbing, but if there's a easier way, why not? Right?

stainless steel cup

ceramic mug1

ceramic mug 2

Well, I used the water from vacuum flask, it was boiled like 3 hours prior. The recommended temperature is above 80 degree celcius. Only some bubbles are formed and visible on the stainless steel cup. Other 2 ceramic mugs looked calm, unlike the illustrations on the seller page, the pictures showed a lot of bubbles.

only minor bubbles on the water surface

After around 45 minutes (the instruction mentions 15 to 30 minutes), I  removed the water and slight scrubbed ceramic mug 2, which was the dirtiest. The wall of mug 2 is cleaned but the bottom still with some stains. Ok, so I waited for additional time for two other cups.

cleaned but not totally clean (ceramic mug 2)

For the stainless steel cup, I cleaned it after 2 hours. The stains are mostly gone. However, if I scrubbed it, the stains are quite easy to scrub off too. Ceramic mug is harder to clean. 

most of the stains are gone (stainless steel cup)

Lastly, after 4 hours, I cleaned the ceramic mug 1. Well, the coffee stains are mostly gone, even the bottom part. But the tiny black spots are still there. I read in reddit, many commented that it was metal particles from the spoon from too much stirrings. Well, as long as it's not mold, I am ok with it. 

stains are gone but there are still some black spots (mug 1)

Conclusion, for this active oxygen descaling tablets, it is kind of useful to remove coffee stains. However, one can use also the clorox to clean it and don't need to use hot water!