what chemical to clean the pcb after leaking capacitors

[Terry Bites]

I think Mr C would say if he was using acetone or ipa instead of laquer thinners.
Have a look at this evil cocktail.

[David Hess]

Acetone and isopropyl alcohol are at least miscible with water.

Aluminum electrolytic capacitor electrolytes are typically something like boric acid and ethylene glycol so a majority of the cleaner should be simple water.  The components of lacquer thinner are less useful here.

[helius]

Lacquer thinner is made for one thing only: spraying nitrocellulose lacquer coatings.
The process was invented in the 1920s and relies on multiple solvents with varying weights. The lacquer-solvent mixture is super thin as it exits the spray nozzle, and enough solvent evaporates in flight to make it significantly thicker by the time it hits the workpiece. This makes it possible to spray vertical surfaces without runs.

As I said on page 1 it has no application to electronics.