I just finished a complete rebuild of a La Pavoni Professional 1984 machine, and along the way I learned a few tricks that might help others out there.
First off is my toothbrush mods. I used 3 different shaped toothbrushes for cleaning this espresso machine. Each has a different angle on the head giving me a wide range of possible cleaning angles.
These first examples were warmed over the gas stove or heat gun and shaped. They work okay, but you have to be careful not to bend directly behind the bristle row or you'll end up loosening and have to pull one row out:
I came up with a better method for shaping these by mistake. Heat a pot of water to 195F put the end you want to shape into the hot water, just touching the bottom of the pan with the solid plastic. Keep a slight amount of tension on the brush until you feel it start to give, once it starts to give you'll be able to pull it out of the water and quickly shape it any way you want. (I do this with latex gloves on so I don't get burned by the hot water.) You can get smooth curves this way. Run under tap water to cool and set in position. My toothbrush is Gum brand, and the bristles seem to hold up well at this temp without curling:
I have brushes shaped to clean the inside lips of flanges, bottom areas and general cleaning. They worked very well for me.
When I purchased the La Pavoni the portafilter handle was rusted, split, and the handle bolt just wouldn't come out of the portafilter holder. I tried WD40, orange solvent, heat - heat & more heat, citric acid, coffee cleaners, and probably a few other things. All I seemed to succeed in doing was discolor the chrome on the portafilter with all the red hot heat and break the bolt off with less than 1/2" sticking out. Finally I tried drilling out the bolt, but my starter drill bit snapped! More heat and some time later I was able to drill it out to 1/4", but still no way to get that bolt out. This portafilter costs $100 to replace and being cheap I began looking around the internet I was able to find that ALUM, a food pickling ingredient, would dissolve iron based metals out of brass without harm to the brass at all.
So I purchased 4 x 2oz packets of Alum at the grocery store for around $4.50 total. Placed it in an aluminum pan, pyrex would be better, put in enough water to cover my portafilter, and heated it to just below boil. You'll know when you have the heat right as the steel area will bubble profusely. It has to be very close to a boil to work fast. Over the period of a few days I would heat up the mixture, keep an eye on it for a few hours and then turn it off, repeating until finally today the steel was gone. So happy me, I now have a portafilter that can be saved even though it looks like it's been through hell. (For a portafilter it has been through hell: heated red hot, had nut brazed to the bolt, heated red hot on the brass, brass melted slightly, blistered chrome, nothing a pretty silver color anymore either. I think it will burnish to a nice grey satin finish when I'm done cleaning it up.) Beware that this will dissolve other steel pots, and as I can attest will de-anodize your aluminum pots. Pyrex would be the best choice if you have it, or possibly a small crock pot.
I used a file after steel was dissolved to true up the edge of the portafilter; thus the shiny edge there.
Hopefully these little tricks help someone else out there, as this was a great help in cleaning this old and neglected Pavoni.