Hi,

I got an Olympia Cremina 67 for free (lucky one!), and I just dissassembled it to clean it properly from the inside. The inside of the group was extremelly dirty (which I cleaned it with soup+water and a toothbrush - clearly the previous owner didn't do the maintainance for a long time), and the piston looks like the youtube video I'm attaching below. I saw Orphan Espresso's youtube videos where he cleans it with water and soup and let it soak overnight. I tried it a couple times and it looks the same, apparently it needs something stronger.

Here the video: What I'm wondering is:

1)Is it safe to use a citric acid+water solution on this part and let it soak overnight?
2) In case it's not, what product would you recommend for a proper cleaning?

Thanks a lot in advance!

Ok, I made a mistake on the main post. I thought Joe Glo was just a brand of regular soap (sorry, I'm very new at this). Orphan Espresso actually cleans it with Joe Glo. I'll try this first (I'm replying because I couldn't figure out how to delete the post :S)