There have been discussions before on HB about brass and copper machines and their advantages and disadvantages. There are some techniques that can keep such machines beautiful without constant polishing and cleaning.
The brass portafilter on the left and the bronze one on the right come from a 1999 and a 1978 Europiccola respectively. They have both been stripped of their original polymer coating.
Neither of these has been polished for over three months! A day hardly passes without using the brass one, and the bronze one gets used at least every other day. After each session I immediately wash what ever portafilter was used under cold water, dry it with an ordinary towel, and then wipe it with a flannel strip about 8 x 40 cm that has been used in the past to polish brass, so it has some barnesite or cerium oxide polish on it. I only go over it once each day, and it looks just as good as when polished three months ago. (Without drying it, and the "once over" with the flannel it would look drab and ugly.) This takes only a few seconds per day to keep looking so good!
The 1999 Europiccola boiler and everything soldered to it is NOT and was NOT coated with any polymer when I got it. About once every two months I remove the plastic sight glass cover and polish the copper boiler and soldered on brass parts with "Brasso" or Simichrome polish, whichever I locate first! As oxides form on the copper the colour changes, it is at its best appearance, I think about a month after the polish phase. I last polished the boiler on 30 October, today is 4 December. Here is what it looks like now:
The polymer coating on the group is beginning to deteriorate. I plan to strip it the next time I disassemble it. I then plan to wipe it with the same cloth after each use, one wipe a day takes the place of labour intensive polishing! Bare brass actually looks better than coated when kept in good condition. The simple wiping really is "instant polishing". A simple daily wipe is all that is required to keep it in perfect polish.