How to spot old gems?

Hi guys. I noticed that some people spot coins that looked dead for months and those coins skyrocket from 10k mc to like 200k or 300k or sometimes even pass 1 mill. How do they find them? I know that certain things might help like an active community or a new cto months later at that 10k. But in order to see these things you need to find the tokens 1st. How do they do it? Are there certain filters they use on dex?

Anyone who does this want to share? You can even dm it too me if you dont want too piblicly share since these people i follow dont want to publicly share their strat