Recently had my car serviced and enquired about having the wheels sorted (I've kerbed 3 of them) the dealer told me to hang fire because if they rusted before the warranty runs out I would get them replaced. I only have 2 months warranty left. What are the odds?

Alloys dont Rust

Think he means pitting Gord

Well thats what I was thinking but the man definitely said rust. What exactly did he mean? what is pitting? Is there anything I can do to ensure I get these alloys replaced?

er....wash then with some kind of acid??

Pitting is like the alloy having a rough feel to it and no shine. Or starting to flake.

The garage I use call it scabbing.

The alloys go like this.

It's pitting mate - very common on Lexus rims. Warranty job!

I am puzzled why you are desperate to get your alloys changed under warranty when they are not actually showing disintegration - and you only have two months left for it to appear to the extent of getting them changed free of charge..... They wont get changed under warranty unless the problem is evident obviously.Also surprised to find a lexus owner who does not know of the wheel problem anyway!
I think you need to accept that you were one of the lucky ones as far as the wheels are concerned, mine have been changed but the finish was not the same, and not quite so nice as my original wheels, which had a sort of frosting on part of them. Your problem is, as you said, kerbing, and no one will change them for that!!

If you REALLY want a new set of rims, try leaving the wheels dipped in salt water overnight

Alternatively dig deep in the pockets and aquire some new rims

What does the salt water do and how quick does it have an effect?