People on JSPS and other postgrad scholarships: how do you get into this area if you finished your degree several years ago and have no experience with applying for these things?

I did all my postgrad work here while working, so I paid tuition from my salary and have no idea how you apply, who is eligible, etc., and while the websites seem to indicate that recent graduates are technically eligible, what is going to happen if I go to one of my professors and say I want to do this? I don't want to ruin all I accomplished and destroy what respect they might have had for me by displaying ignorance.

There is still some progress left to be made in the tiny field that I studied and some of the informants I worked with are getting very old. I'd really like to try to make these advancements while it's still possible.

While in grad school I met a few people on these scholarships but didn't ask about their backgrounds. It seemed like they had only ever been in academia, with no interruptions. Has anyone heard of someone who finished their degree, worked in an unrelated field, and then tried to get back into the academic world?

I'm also old by these standards. I've heard rumors that the age limits were being eliminated; years ago you had to be under 35 for some of these.

(Please, no "google it"; this is the stupid questions thread. I'm looking for personal anecdotes and opinions. Can't ask in the real world for fear of embarrassment.)