As I understand it, the IPA isn't used for degreasing. When you use an abrasive compound polish, it polishes the surface but the oils in the polish (either as an ingredient or as a result of breaking down the polish), fill any minor swirls in the paintwork thus "hiding" them. The IPA is used to remove any polish residue and oils so you can see the true surface, hence you don't need much.

TBH I've used 100% IPA (in an aerosol can and sprayed on to a microfibre cloth) without issues but am trying to prevent any further problems.

That is what I meant by degreasing. Oil is not miscible with water, so you need something else.

Fairy liquid is even more damaging. It actively roots into any pores in the paint, has a high salt content and generally does your paint no good.

Anything from a cosmetic product is no good for optics, they will leave residues such stabilisers and humectants.

Calm down guys its only my 2euro reading glasses just need them clean enought too read through ...

Honestly, get a decent microfibre. Hell get the Belkin kit if you're feeling flush.

For some reason, you can dilute IPA w/ distilled water despite thinking it'd be immiscible.

Alcohol that didn't mix with water would lead to a dull life.

The OH group on alcohols mean they can hydrogen bond with water, so it is water miscible in a way that pure hydrocarbons are not.
I have no real idea about the relative merits of a water / alcohol mix though (except as a drink, as per Matt). I'd guess the more alcoholic it is, the more oil it can hold.

It would be insanely expensive to wash a whole car in it though, not to mention illegal in many countries because you must not dispose of it down the drain.

As for glasses, I use a very convenient source of pure distilled water. I huff on them.

mmm huffing.

Bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored, bored.

with the baseline residual alcohol levels in your exhaled air, it's probably not that far off the IPA mixture described

But you don't wash the car in it. I soak a microfibre with it and then go over the car. You should only polish a car once or twice a year at the most. Hence you're not going to use litres of the stuff.

so the rig is working again .....

I find that as it progresses through the night, I have to zoom in more to be able to read anything!