fixing fuel system on a 1983 240d

[why-is-my-username-taken]

I have a 1983 240d with 201,000 miles that hasn't been run in 3 months and am wondering if I need to clean the fuel tank and how I would go about doing that.

also, I will replace the fuel lines but can't seem to figure out which ones are high pressure and which ones are low pressure as well as how to relieve the pressure from them.
any and all advice is appreciated thanks.