Greenwif wrote:
I've got access to some very large used catering size food oil cans.
They are quite colourful and thought it would be fun to grow some veg
in them. i've seen this done in South america. But I'm at a loss as
how to remove the lids, as at present all they have are holes punched
in the top to get out the oil. I'm sure my normal kitchen can opener
would not cope with the thickness of the metal. Any suggestions?

You may be surprised, give the can opener a go. The main problem is not so
much the thickness of the metal but the depth of the rim at the top that the
opener may not be able to clamp on to and still cut the lid. I assume you
have the kind that cuts the lid, the kind that cuts the side of the can
leave a very sharp edge as the folded rim is removed.

If that doesn't work you can use a can triangular punch all the way round
the edge, this will leave a series of triangular tags of metal attached to
the rim that will have sharp edges, once you get the lid out you can hammer
these tags down flat on the inside and they shouldn't be too dangerous. Any
kind of saw (jigsaw with a metal-cutting blade) or abrasive cutter will also
leave a nasty sharp edge that you will have to deal with.

In desperation (who didn't pack the can opener?) I have opened cans with a
knife but if you don't have the right kind of knife and sufficient control
of it this is a risky procedure as you can get a nasty cut from the knife,
the sharp edge of the can or both. If doing it use a knife with a short
strong blade and hold the can in some way so you can control the knife with
both hands. If you don't have strong hands don't try it. I would leave
this as a last resort.

BTW what do mean by 'very large'? If less than 10 litres you may be largely
wasting your time.

D