dawn soap and a tooth brush.bathroom cleaner if really filthy..nothing caustic on early gillette gold surfaces..there are more germs on doorknobs..
Palmolive dish soap, and an old toothbrush, with warm water. If it is sticking, then a little more effort needs to be put into it. https://theshaveden.com/forums/threads/cleaning-stuck-and-crudded-up-razors.64405/
For general cleaning just hot water, a soft tooth brush and Dawn dish soap. That's it. I rinse my razor under running hot water and wipe down after each shave. It adds only an extra 60 seconds to my shave and it has all but eliminated the need for me to do monthly general cleaning as noted above.
I'm with the other guys about Dawn. Ever since the virus thingie, that stuff's been selling like crazy due to its germ-killing qualities. Hot water, Dawn, and a toothbrush, as often as needed to keep the soap scum from building up. Works great.
I took an old ratty Gillette Starburst, that I just bought, and gave it a good boiling water/Palmolive soak. After it cooled I scrubbed it down and it now looks brand new.