Floor cutting - isn't alu supposed to be soft?!

[jps]

Been trying to cut out the floor panel today. I'm going with what I could get for free - which is a 3mm thick sheet of alu - no idea what grade - but it is an old pub sign.

Anyway - i'm getting through jigsaw blades at a tedious rate. I am assuming this is because the alu is so soft it is clogging the blade. The cutting disc on the angle grinder was worse than useless - presumably for the same reason.

Am I right - and what can I do to cut the alu more easily / without the constant snapped blades!