I tried a new recipe last year, boiling the fruit first and then (once cooled) halving them, removing the pith and "innards", saving pips, etc in muslin bag for pectin. This worked very well, and slicing the skins was so much easier - I quite enjoyed the task. Have tried using a food processor, but I find the chopped remains can contain larger bits which need to be sliced anyway. Allowing the marmalade to cool for about 5 - 10 minutes means the peel is dispersed throughout the jam. I don't really like "bits" as a rule, but they are so soft and flavoursome in home-made preserves, I now enjoy them. I also follow WI method for sterilising the jars: wash in warm, soapy water, rinse and leave to drain thoroughly. Then into a warm oven gas mark 3, well-spaced on a baking tray for 30 minutes. Well worth the effort!