Alright mate, just having a nosey and noticed thread.
I used a bit of white spirit on my damp scrim, always found it brought a nice sparkle to the window. Picked the tip up from an old window cleaner. Use too much and it will leave smears, just the right amount and it does the job.
It's also good on a hot day and the suns shining, as plain water will dry on the window before you use your dry scrim to polish up.
I never used it in the water, so whoever said that has it wrong, it was always on the damp scrim. Meths or turps will leave smears, never used those. If i used applicator and squeegee on the window white spirit was never used, it was just the damp scrim.
Doesn't ruin the lead either, i've used it for years, swear by it, but each to their own i suppose. Thought you were wfp'ing anyway?
Paul