So when my La Pavoni arrived it was the first time I'd even seen one in the flesh, so although I was reasonably familiar with the whole machine through extensive research, when I saw this brown grease like substance underneath the sight glass cover, I assumed it was meant to be there. The whole machine was like-new, so it didn't really cross my mind that it wasn't meant to be there.

So a few months down the line and it's completely welded to the machine. It's dripped down the backside of it (so just out of my line of view where I have it setup, otherwise I would have seen it), and is now rock-solid. It took me a good 20 minutes to get the sight glass cover off and try and clean it because it had been welded on.

This isn't normal, is it? I think the sight glass cover will just need to be replaced, as it doesn't want to come off. The only way I could get it off the chrome coating was to very carefully scrape it with knife - not ideal.

Does anyone have any suggestions on what can be used to clean this without damaging the coating? As there is residual brown gunk glued all over it.

As for what it is, I can't seem grease doing this. And it's a coffee machine, and it's brown, so I guess it could be coffee. But how there would be coffee under and only under the sight glass cover is a bit bizarre...

I will assume that you have a newer machine with the plastic cover.

It's not grease, but glue. It sounds like yours had a bit more than mine did, but it is hard to clean When it heats up it softens, runs, and fouls the plastic cover as well. I can't remember the solvent I used to clean it off, but it was probably alcohol, mineral spirits, or acetone. Still I remember some very stubborn bits that needed scraping off with a razor blade. That was on the surfaces of the sight glass fittings.

The funny thing is that the cover stays in place too well by itself with no glue. The tabs that hold the cover on are so deep that after a few years when the plastic becomes more brittle it is difficult to remove the cover without cracking it. Before I installed my new cover I shaved down the tabs until they were practically flush. Now it snaps in fine, but removal is really easy.

That's bizarre, why on earth would they want to use glue on that thing? You're right, it just snaps in place and doesn't need any glue. Thanks for the tip on shaving down the tabs for if / when I replace it.

That makes it easier anyway, knowing it's likely glue. I'll give some acetone / nail-varnish remove a go. I'm sure it'll probably strip the protective coating on the chrome as well, but it looks awful as it is...

I don't think there's a coating over the chrome. At least mine doesn't. After all, the chrome itself is plated over nickel to preserve the bright polished finish from tarnishing.

I feel like I'd read that there was a lacquer finish over the top of the chrome plating, which is why it's not recommended you use soapy water to clean it, because it can eat into the protective coating? I can't quite that source though, so it may all be hogwash.

Brass and copper are sometimes lacquered to prevent tarnishing, and I understand that La Pavoni does this (or has in the past). Maybe that is what you are remembering.