Can I use Grade A Ilex Lacquer Thinners to clean of flux on boards containing programmable IC's without it damaging or compromising any of the components.
Isopropyl alcohol (or even ethyl alcohol; there are better uses for it) is the recommended solvent. IPA cleans solder fluxes very cleanly. If the PCB is visibly clean, you can even use distilled or deionised water (do not forget to blow dry) to clean it further.
External bodies should be cleaned with a damp cloth- I routinely use damp paper towel even for the monitor. Lacquer thinners contain very aggressive solvents (it is a mix).