Is leaving food in an open tin harmful?

[flobadob]

Is it harmful or poisonous to open a tin of beans or spaghetti but only use half of it and keep the rest in the tin to be used in a day or two? I always assumed it was, but is it really?

[hammerman]

We've done it for years and we seem alrlkdflpgpw4po5io

It's not recommended as the tin can react with the air and oxidise or something but we've always done it.

[Nannyjillx2]

I do sometimes if I'm using it the same day otherwise I out in a dish and cover.

If we believed half of what we read we'd have no life just spending our time doing x y or z. People have survived for years doing these things.

[MrHurlAbuse]

As hammer and nanny said,ive done it for years even though ive heard the correct way is to put in a plastic covered dish!