I think this paper can be useful for you

Dear Vinod Belwanshi many thanks indeed for your interesting technical question. I can try to answer it only from the viewpoint of an "ordinary" inorganic chemist, i.e. no guarantee! I have personal experience only with cleaning laboratory glassware, but not stainless steel parts.

As for the glass chamber we should consider that both metals, indium and lead, can be dissolved in nitric acid. Thus my suggestion would be to rinse the chamber with concentrated nitric acid (69%) to dissolve the metals. Remember: This works only if the stainless steel parts can be completely detached prior to this treatment. Then wash with distilled water and dry in the oven at 120 °C. If any joint grease is involved, this can be dissolved by immersing in a base bath of ethanol with dissolved KOH (not too long in order to avoid etching of the glass).

When you search the general internet for "Guide to cleaning laboratory glassware" you will find numerous useful link auch as e.g. this one entitled

How to Clean Laboratory Glassware

https://www.labmanager.com/lab-health-and-safety/how-to-clean-laboratory-glassware-20325

As for the stainless steel part, I would like to suggest the following potentially useful articles:

1. THE CARE AND CLEANING OF STAINLESS STEEL

and

2. How to Clean Stainless Steel for High Purity Applications

For your information please find attached pdf files of both articles.

Good luck! 👍

Dear Frank T. Edelmann , It is much appreciated that you have taken the time to respond to my question. Many thanks! Your post is very much informative and useful to me.

Indium residues can be etched/dissolved with diluted nitric acid at room temperature or with hot (to boiling) hydrochloric acid.