I was refering to multimeters which can measure temperature and for this purpose they come with a thermocouple probe.
If you dont calibrate with something like that, then at least keep in mind that what shows 200C isnt the real thing, it could be 240C. There is no absolute reference anywhere. If you put in table a value like 1million degrees, that is what pronterface will report you: your hotend will have around one million degrees. Its very important to be aware of that. Fortunatelly in your case it shows less than it is. For example you seem to use like 200C for ABS printing, while the real temperature most likely is around 240C. If it would of been the other way, say it would of shown 240C when real temperature would of been 200C, then you would of tried extrude abs at real 200C, which means you would of tried to force extrude a cold plastic and could get something broken.
So you dont have an absolute reference and cant trust what your readings are like (not calibrated), then if you get a plastic and you dont know where the extruding temperature should be, try finding best temperature like the following, "by hand". Take away the bearing that pressures the filament onto the hobbed part, so you can push the filament by hand. Heat up the hotend at different temperatures, slowly increasing the temp setting, and try push the filament by hand - gently. As the temp increases, you will find a first point where the filament starts to be pushed fairly easier. Following that point, it becomes easier and easier, untill the effect levels down. Meaning regardless if you increase the temp, the plastic doesnt seem to be any different in pushing through. Basically it stops being related to temperature, and it is fairly easy to push through, and it doesnt become any easier after. This or the first part of this is a good setting, see what temp says it is and use that. Extruder will need least amount of force to do its job, so extruder will be happiest with that setting. Its pretty weird to try explain this, but i am confident that you will better feel it at hand and will understand when you try it.
If you dont try to find at least a good setting like that, then you just "guess" a setting, which you did. If such setting is before that "easy pushing" interval, then you dont realize it. You cant see that extruder has a hard job to do. But you are rather forcing the extruder coz it needs more force than it should. So that explains the chips of filament on your hobbed bolt area. Once you find its good setting, the hobbed area should be clear of abs chips and shouldnt require cleaning at all, not even once per year.
If you dont calibrate with something like that, then at least keep in mind that what shows 200C isnt the real thing, it could be 240C. There is no absolute reference anywhere. If you put in table a value like 1million degrees, that is what pronterface will report you: your hotend will have around one million degrees. Its very important to be aware of that. Fortunatelly in your case it shows less than it is. For example you seem to use like 200C for ABS printing, while the real temperature most likely is around 240C. If it would of been the other way, say it would of shown 240C when real temperature would of been 200C, then you would of tried extrude abs at real 200C, which means you would of tried to force extrude a cold plastic and could get something broken.
So you dont have an absolute reference and cant trust what your readings are like (not calibrated), then if you get a plastic and you dont know where the extruding temperature should be, try finding best temperature like the following, "by hand". Take away the bearing that pressures the filament onto the hobbed part, so you can push the filament by hand. Heat up the hotend at different temperatures, slowly increasing the temp setting, and try push the filament by hand - gently. As the temp increases, you will find a first point where the filament starts to be pushed fairly easier. Following that point, it becomes easier and easier, untill the effect levels down. Meaning regardless if you increase the temp, the plastic doesnt seem to be any different in pushing through. Basically it stops being related to temperature, and it is fairly easy to push through, and it doesnt become any easier after. This or the first part of this is a good setting, see what temp says it is and use that. Extruder will need least amount of force to do its job, so extruder will be happiest with that setting. Its pretty weird to try explain this, but i am confident that you will better feel it at hand and will understand when you try it.
If you dont try to find at least a good setting like that, then you just "guess" a setting, which you did. If such setting is before that "easy pushing" interval, then you dont realize it. You cant see that extruder has a hard job to do. But you are rather forcing the extruder coz it needs more force than it should. So that explains the chips of filament on your hobbed bolt area. Once you find its good setting, the hobbed area should be clear of abs chips and shouldnt require cleaning at all, not even once per year.