Reccomended ways for to clean off well the glass inner surface of these empty tanks?

[TiercelR]

Hello all.
Please can you recommending to me a some ways for to clean off well these empty tanks?

Here i has added 3 photographs ( that shows from their outside ) one of my empty tanks which is suffering this situation.

I have 4 empty tanks with this problem.

Apparently this is a sort of mineral remains that are quite sticked onto the inner surface of these empty tanks.

Possibly this is relationated with the water quality.

Thank you very much in advance for your replies. Regards !

 

[AmyKieran]

You could try delicately using a glass scraper with a blade? Usually available in hardware stores

 

[Lynnzer]

Vinegar is the easiest way. Just spray and leave but keep it wet by spraying more so it can do its work. Then a brisk rub with fine cloth.
It looks like some sort of limescale build up but in any case vinegar should take care of it

 

[TiercelR]

You could try delicately using a glass scraper with a blade? Usually available in hardware stores

AmyKieran, many thanks for your reply, i will purchase one ! Regards.

Vinegar is the easiest way. Just spray and leave but keep it wet by spraying more so it can do its work. Then a brisk rub with fine cloth.
It looks like some sort of limescale build up but in any case vinegar should take care of it

Lynnzer, many thanks for your reply, i will do it so too ! Regards.

 

[Rocky998]

I sexond the vinegar... Maybe combine using vinegar and a scraper. Just be careful not to scrape the glass. Also rinse it out really well after you wash it out with vinegar.

 

[PheonixKingZ]

A third for the vinegar. The way I clean my old tanks is I lay it on it’s side and pour a thin layer of vinegar on it. I then let it sit for about 15 minutes and then repeat that on all the other sides. After I let all the other sides soak, I clean it with windex. After that, I wash it with hot water.

Some people recommended using a straight razor blade to scrape off the calcium deposit, but in my experience/opinion, it’s just asking to get cut. It’s also a lot more work than is necessary. The vinegar does most of the work.

 

[TiercelR]

I sexond the vinegar... Maybe combine using vinegar and a scraper. Just be careful not to scrape the glass. Also rinse it out really well after you wash it out with vinegar.

Rocky998, thank you so much for the advice. Regards !

A third for the vinegar. The way I clean my old tanks is I lay it on it’s side and pour a thin layer of vinegar on it. I then let it sit for about 15 minutes and then repeat that on all the other sides. After I let all the other sides soak, I clean it with windex. After that, I wash it with hot water.

Some people recommended using a straight razor blade to scrape off the calcium deposit, but in my experience/opinion, it’s just asking to get cut. It’s also a lot more work than is necessary. The vinegar does most of the work.

PheonixKingZ, thank you so much for the recommendations. Regards !