One of the good British horologists has an argument as Bob has stated that if a clock is oiled properly then oil sinks are not needed. I cant remember his name but a very well respected guy. Also as Bob said and I completely agree with him it is best to keep the clock as original as possible but this is not always easy with a customer who wants the cheapest bill and isnt worried about having the clock completely original. All you can do in that situation is state that the clock will be more valuable if left original, if they dont go for it then you have no alternative. I have seen the complete striking train removed from clocks because the owner didnt want it to chime. May have seemed a good idea at the time but what a shame now 
Just my two cents 
