'Flux rarely causes a problem during the warranty period - especially the no-clean stuff'
But years-on in certain circumstances of temperature and humidity it can become a problem for RF and power circuitry?
I generally clean it off.? ?The no clean fluxes may require a specific cleaner like ECSP or FLU FluxClene? (both of which can often be ordered with a handy Brush) but many fluxes come off with just Isopropyl Alcohol
Bruce Akhurst