Q from my dad, bless him, about white deposits left behind on plastic containers from the dishwasher

[dandycandyjellybean]

When I take some plastic food containers from the dishwasher that have
had sauces that contain tomato they always seem to have white deposits
in them. The deposit is really stuck to the plastic and is difficult
to remove. It will not soak off but has to be scratched off. I have
looked on the net but can't find any suggestions. Any thoughts from
Mums net maybe?

Thanks

DAD XXXXXXXXXXXXXXXXXXXXX

Anyone? Can we keep his faith in mumsnet?

Is it melted? I think it's unlikely to be a stain. I don't own a dishwasher though so am probably wrong.

I have these all the time on the dcs plastic bowls. Really irritating. I thought they were possibly calcium deposits as they do scratch off.

I get this on certain plastic plates and have assumed it is actually plastic rather than deposits. I wash those ones by hand now.

You get this if the tubs have been reheated in a microwave, where the tomato sauce gets very hot . It's heat damage, not from the dishwasher.

My bowls with the white bits in them haven't been in the microwave... The way it scratches off I'm still going with calcium deposits. Melted plastic won't scratch off like that.

I get this and not linked to tomato sauce. Think it's the dishwasher somehow.
We hve hard water do you? Could be something to do with that?

I always assumed it was salt, but calcium sounds plausible!

well that's odd.

there shouldn't be calcium, if you keep the salt reservor topped up. But will you scratch a bit off and drip vinegar on it? It will fizz if it is calcium carbonate or similar.

How cool is your Dad?
I dont put plastic stuff in the microwave usually because it goes orange so no help to you.

Piglet - no discernible fizzing here

I'm pretty slack at topping up the salt thingy in the dishwasher tbh, though I do use all in one dishwasher tablets so I assume the salt in them will prevent too much calcium build up.

'mmm, no fizzing. If you scrape a bit off and put it on the hob, does it smell of burning plastic?

I'm pretty sure I've only seen it on plastic tubs that have been through the microwave, can't imagine what else could cause it. It couldn't be dried-on mashed potato or something, or cooking fat, could it?

BTW 5-in-1 tablets are not as good as keeping the salkt container topped up, for preventing limescale. If it is a Bosch or similar machine, it probably has a hardness-setting little blue dial tucked away top left corner inside the door frame.

I get his on DS's little pots I put his fruit in, they've never had tomato or been microwaved, just through the dishy.

Lol Piglet - if i scrape a bit off and try and cook it, should I put it in a saucepan first? Can't see how to cook it on top of a naked gas flame otherwise!

I'm pretty sure it's not dried on food, though some may be dried on mashed paper - from labels of jars that have also gone through the dishwasher, but I can't imagine that's all of it?

I just accept it until it gets really bad, then recycle the plastic and replace.

It's the plastic responding to the high temp. I would bet that anything that claimed to be BPA free would not do this.

but doesn't occur only on the inside of the tub, round about the fill mark? Mine do, so I'm sure it must be caused by food traces, not just heat and not just the dishwasher.