Cleaning Lime Scale From Pots

[Shane]

Beautiful pot Joe. Has anyone any thoughts on just running pots through a dishwasher? Perhaps not on delicate pottery like the one above, but I tried it on a couple of my training pots to make sure any diseased soil from previous occupants was removed. Came out cleaner than when I bought them. Cheers Shane.

[bonzaidog]

Great idea Shane! ...you're obviously single though! ....Dog

[Jow]

Ok, so a night and a day of soaking in coke had little to no effect.

The dishwasher sounds like a good idea but I don't think I'll go down that path with this pot. It's a little on the delicate side.
I am also reluctant to scrub the tiny fins either for fear of breaking them.

Time to try straight vinegar?


The after coke results.

[bodhidharma]

Wow, that is a beautiful pot Jow. I can make out most of the detail but what is the representation in the centre.? they look like spoked wheels. Can you make it out better in the flesh and what is it. The mountain in the background and the tree is obvious.

[Jow]

I think it is an over grown water wheel. Its a strange image for a japanese pot though as i always think of them as more of a western image. That said they do exist in Japan.

[JR_J]

Great pot Joe,
I agree with Leigh - I use "Crean Mate" on my pots too - it does work a treat! However, not sure if I'd do it on that pot, looks very delicate. Try the white vinegar on the base first in case of stain marks?!
Cheers,
Rudi

[gollum]

another option is CLR
it would surely remove that buildup without any scrubbing
never tried it myself but it is supposed to dissolve calcium lime and rust

[63pmp]

The scale that builds up on pots is a combination of phosphorus and sulphate salts. It is not lime scale. Your potting mix and water would have to be at a pH of 8.4 for it to be lime. It might be bicarbonate salts, these will fizz like alka-seltzer in the presence of an acid such as vinegar. However this is unlikely and so it is mostly phosphate salts from over fertilizing with phosphate. It is made worse in the presence of calcium. So if you have hard water, or use things like DL, blood and bone the scaling will be worse.

Phosphate salts are very resistant to dissolving in water, which is why your teeth are made of it. The best ways of removing salts that have built up on pots, or if there cheap Chinese pots, in the pot, is to throw them into a swimming pool for several months. Other then that bury the entire pot(without the tree) in a garden bed, soil microbes will consume the salts, much like microbes dissolve your teeth. Do not ever use a clean mate as it will ruin a pot. especially a glazed one. (In fact, you shouldn't use a clean mate on your tools as it will ruin them as well). You can also stop fertilizing with phosphate for awhile, more then likely there is enough phosphate salts in the potting mix to keep the tree happy for a month or so, eventually the scale will dissolve, rot , disappear.

Cleaners that contain citrus oils such as the orange extract type cleaners will do a better job than most, but avoid rubbing your pot with anything as this will damage the patina and surface.

Paul

[Pup]

Thank you for that information Paul, I have stopped buying second hand pots that have scale on them, no matter how nice as the hassle to clean them has become more of a problem.

One question though Paul, Why not use the clean mate ( crean mate )?, over the years I have been using it, I have seen no detrimental affects on my tools.
I do clean them after each use, and treat them with wd 40, and in the 28 years now, no problems.

Thank you, Cheers Pup, Oi Oi Oi

[63pmp]

Hey Pup,

I've found the crean mate tends to round off sharp edges and create hollows where there not needed.

The black stuff that forms on tools can be removed easily by scrapping with a utility knife, which leaves an even and smooth surface and won't damage the steel. The crean mate will take some of the surface steel off with the black stuff (which is iron stannate, a reaction of iron in the steel with tannic acids in the sap), while it leaves a clean surface, it is no longer even or smooth.

On sharp edges, such as scissors, branch, knob and concave cutters it will eventually change the angle of the cutting edge, if not rounding it off so it's dulled.

The angle of the outside cutting edge on branch cutters, right up to the cutting edge, is critical for clean cuts. Rounding of the edge here will cause the cutter to bind in the cut and create tear out. Because the crean mate is somewhat soft it deforms on edges and rounds them off, effecting the surface angle.

The clean mate is Ok on handles and such for removing rust, but don't go near the business end of tools.

As for pots, it's far to abrasive, it will leave scratches on the surface of the pot.

I used a crean mate for years, but found tools did better without it. I use a cheap 2 dollar utility knife to remove black stuff, and If I need to remove rust and stuff from the cutting area, it's probably time to sharpen the tool. I use, or handle my tools, just about every day. I have four or five that never go back into the tool box, but stay on a bench cause there used so frequently, handling this often prevents rust from forming. I recent Fine Woodworking article looked at rust inhibitors and found WD40 was equal to the best rust preventative treatments available. Its good stuff and cheap.

regards

Paul