Stored in vacuum bags with dessicant?
Or stored on a shelf in the open?

Either I'd buy one known good roll to calibrate your printer, then take it from there with he old stuff, see how good/bad it is.

A filament dryer might something to look into.
There's also a case to be made of not buying more filament than you can use to avoid these situations where you're stuck with old sketchy stuff.

Definitely go first with a new spool of well-known filament. Though I have had very good experiences with old filament, I recently had an issue with a spool of PET that would not adhere to the bed, and I tried drying it out for several hours. Mind you, this same spool had worked wonderfully in the past but I don't know what happened to it. Imagine that you tried to use a spool like that to calibrate your first layer!

Are the filaments still in their original packaging and if not, how were they stored? The main thing with old filaments is how much water they've absorbed from the environment, with older filaments stored in high humidity environments causing issues for print quality.

If your filaments have been stored sealed in original packaging, they'll probably print like new. If they've been stored in an airtight container they'll probably also be pretty good. You can also just give them a shot and see if you're happy with the quality they provide.

If they've been stored open on a shelf, it isn't necessarily over for them though. Look up guides on how to dry out filament. There's a few products you can buy that do it too, but if you have a printer with an enclosure and heated bed you can use that as an oven to bake out your filament.

I've got a few filaments that have been sitting for over 6 years and after baking out they print absolutely fine.

I would say dry the shit out of those old filaments, and then send it.

You've already invested in them. The only thing you have left to waste now is your time.

Arguably speaking, even new filament can be wet, so a filament dryer would be necessary regardless of what you do.

If it's PLA or PETG it's probably still usable. PLA can get brittle if it's wet though but drying should make it usable again.

I use a cheap food dehydrator to dry filament.

I left my 1 year or so in the garage rolls in the dehydrator for two weeks and a bit (forgot about them) and they printed seemingly fine

i recently got back into printing. I had some PLA, some PETG, some ABS and some ASA all of which had sat for longer than that. After thorough drying in a dehydrator, a couple of rolls just didn't cooperate but most did. The troublesome ones may not have been very good to start - unbranded mystery stuff.

I've had filaments sit for longer than that, and they're fine. Just loaded some up this morning in my new printer. I do keep my house' air relatively dry.

The climate I live in hasn't ever caused any issues with filament, so YMMV.

I still keep them all in a big sealed plastic box with all the baggies of desiccant I've collected over the years. I give the baggies a yearly refresher in the microwave.