I need to try out some of the suggestions mentioned on here for myself in due course but so far what has worked for me is:-
6mm thick glass covered with Kapton tape applied in 2" strips (it is cheaper). I use window cleaner spray as mentioned previously. Kapton tape smoothed out with a credit card (visa or mastercard OK).
Bed heated to 110 deg C and ABS juice painted on at 110 with small paintbrush. The juice instantly dries on.
Usually one coat sufficient but for wide objects that can lift, use two or more coats.
Get the first layer really squashed down on the bed at the start by adjusting the Z couplings by hand (I have an Ord Bot). It is easy to do visually.
Only downside is it can stick too well but you can't have it both ways. Letting the bed cool down makes it easier to remove.