I have a 1910 Stanley with magnetic metal fragments in the boiler. In past months this residue has fouled my water level gauge and steam automatic - with negative affects. I have been filling and dumping the boiler in an effort to clean it. Question: Is there a solvent or boiler friendly cleaner that I could use to help this process along?

C-o-n-t-a-m-i-n-a-t-e-d !!! Sorry

Tom my old standby is soda ash to clean a boiler. One tablespoon per five Gal of water, let it boil for a while, and then blow it down. Your problem is you only have 1/8 taped hole on the blow downs valves. I never use anything smaller then ¼ inch IPS

If you really want to clean the boiler remove it from the car and install a temporary full port ball valve in where the throttle hole is.
Put it over a fire in the normal position and let it cook for a half hour with the soda ash to a couple of hundred PSI.
Then tip it over and let it sit a while, 15 to 20 minute’s, then blow it down through the large ball valve. Repeat this two or three times or until no more solids come out.
Rolly

For the magnetic fragmentsyou mite try a small greased section of rope with a steel ball of smaller size atatched to it, or some iron bbs and blow them thrue the boiler coil with the end caps off. just like the Hotsy boiler service. or you mite simply ebay Hottsy steam preshure washer components, there was a fellow selling full boilers at a very reasonable price. if they have a modle with same or like volume most are round of like diamiter and hight. and rated to better preshures, though shaped like a doble or white boiler.

For a pressed fire tube boiler?
My best advice would be a light going over with a body hamer, and a good flush wile doing it, so the water remains aggitated. For calification or rust? They sell consentrated bottels of C.L.R. calcium lime and rust away. for pluming issues havving used it before it works well on all iron copper and brass, but should be kept from contact at duration or any strength of % to water when working with aluminum, as if your aluminum is oxidised it will then cause the oxidized portion to imeadeatly begin chemical decomposition.

Thanks All !! (a fire tube boiler - copper tubes on steel sheet)