I don't want to sound cruel but if your plant contracted a virus then I don't think any snipping off of the leaves will get rid of it. Viruses are systemic in nature meaning they infect the whole plant including leaves and roots. That is why most experts would advise to destroy a virus-infected plant by burning it so as to avoid the virus spreading to your other healthy plants.
But if it is just bacterial rot or fungus then cutting off the diseased part and treating it with an appropriate fungicide or bacteriacide will do the trick and you still have your plant.
Also don't forget to flame your cutting shears in between cutting from plant to plant so as to avoid spreading disease inadvertently to your collection.