Wow thanks for all the info WWWired, and baldheadracing thanks for the link to the other thread - that was the other half of my concern.

As for an update, I got some Barkeep's Friend and extra elbow grease, and the PF is looking much better!

most brass alloys have a pinch of lead added to make it more brittle. Machining brittle brass leads to small chips, which is preferable over lead-free brass, which creates longer chips. but the percentage is very low.

the same trick applies to stainless steel, however in this case its sulfur, which makes the chips brittle and small. (making 'stainless steel for automated production' very much no longer 'stainless'...

automatic production needs a good chip handling, as even a days production amasses lots of chips. you also dont want the chips to be wound around your workpiece, or tooling, or flung around your machine, therefore the alloys are modified to facilitate automatic production by making chips brittle and short.

the roman empire fell apart because they used fresh water pipes made of lead, poisoning everybody slowly but steady.
but i wouldnt worry about the exposed brass in your portafilter. if it once was plated, it means that somebody ingested lots of chrome, which is also a very unhealthy heavy metal.

my olympia portafilter also isnt plated. as long as the oxidation is mere discoloration, its all fine. but 'blossoming' oxidation like yours had i would knock down with steel wool. no sandpaper, because: the more scratched up your surface is, the larger it gets, and the easier it oxidates. the more polished and shiny it is, the less likelier it will happen again. like yours is now.

Sw1ssdude wrote:...
as long as the oxidation is mere discoloration, its all fine. but 'blossoming' oxidation like yours had i would knock down with steel wool. no sandpaper, because: the more scratched up your surface is, the larger it gets, and the easier it oxidates. the more polished and shiny it is, the less likelier it will happen again. like yours is now.

Very interesting! So steel wool and/or Barkeeps Friend are ok, but not sandpaper (or grittier things)?

The single strands of steel wool have a triangular cross section, so they act like razors. knocking down high spots while leaving the underground untouched. those soapy steel wool pads are also perfect to get rid of rust on rims, bumpers and so on without scratching the chrome.

cant say about barkeepers friend, as it is not available where i live... but steel wool is very effective, and very cheap

Sw1ssdude wrote: ...
the roman empire fell apart because they used fresh water pipes made of lead, poisoning everybody slowly but steady.
but i wouldnt worry about the exposed brass in your portafilter. if it once was plated, it means that somebody ingested lots of chrome, which is also a very unhealthy heavy metal...

No it doesn't. First, chromium (unlike lead) is a trace mineral that is essential to human health. I know that it's not listed as such in Europe, but it is here in the USA and it is essential because if you don't ingest any chromium at all you will get sick. We found this out years ago when we maintained patients on total parenteral nutrition. Second, the form of chromium that is toxic is hexavalent chromium, which is found mostly in paints and dyes. Trivalent chromium is the "essential" nutrient form, and is the form of chromium found in plating.

ha, you're right. in Europe, Chrome(III) has no beneficial influence on the human body (while its toxic influences are now again evaluated, but more from a galvanic point of view), while in the USA the benefits are still debated.

Anyhow,
I would not worry too much about the lead in the brass portafilter, and if i ever catch the chrome in my portafilter flaking off, i'd scrub that stuff off (don't want my coffee to start sparkling). but i sure dont mind having my coffee running over chromed metal pieces.
I believe (as in: i dont know for certain) that the lead contamination from my bare mid seventies Olympia brass portafilter doesnt kill me, even with multiple espressos a day.

Sw1ssdude wrote: I believe (as in: i dont know for certain) that the lead contamination from my bare mid seventies Olympia brass portafilter doesnt kill me, even with multiple espressos a day.

You might not actually be living longer if you hadn't drunk all those espressos, but it might feel like your were...