[RPG] How to players learn the nature of magic items

I'm running a sandbox campaign with Adventurer Conqueror King System (essentially Moldvay-Cook Basic/Expert D&D). My players are starting to find probably-magic items during their expeditions and they're keen to figure out what they might do. However, as a DM I'm not sure how to adjudicate their efforts to find out about the items they find.

My first D&D was AD&D 2nd edition, so I'm used to there being spells like identify that, though costly, provide a reasonable way for PCs to figure out the nature of a suspected magic item. My default assumption was that I could turn to the "paying for services" section and they could pay through the nose for an NPC wizard in a big city to cast identify for them. There's no such spell in ACKS, so that's not a reasonable default.

How do you handle players wanting to identify the nature of found magic items in your old-school game? What works, what's awkward, what maintains the mystery of magic items and the thrill of discovery?

I want to find out what other DMs of old-school games have found to work from experience, but
I'm not just asking the Internet to solve my problem for me. Here's what I've considered so far and the benefits and drawbacks I've thought of for them, though I haven't put them into practice yet:

• I'm perfectly happy to let the players experiment with their unknown items until they figure out what they are. This is my preferred method, but since I like lots of player agency I'm hesitant to make it the only way. Giving players the choice between between the risky but cheap methods and an expensive but safe methods something I'd like to have in this game. Also, this is a great option for things like potions and magic swords, but no so much for other items. In particular, a PC currently suspects that a case of crossbow bolts is magical – experimenting with these isn't going to make their nature obvious, unless I give them a visual FX or some other "wow that was obviously a magical arrow I just shot that rat with" indication.
• I could just introduce identify or some variant, since that's a legit thing to do in a B/X game. The spell would be jealously guarded by the NPC mages who know it, just like any other spell that's not commonly known. This has the bonus of making experimentation worthwhile since hiring an identify casting would be difficult and costly. It also would make discovering a scroll of identify a very, very valuable find.
• I could give such inconvenient magic items as above some kind of visual FX. This would require the player taking a risk and using the item at all, but fits into my desire to have them experiment. The problem is that I'm not sure that this won't have some awkward corner cases that won't work well. It also doesn't give me any guidance for how to handle a player who is really insistent on finding someone who can magic up an answer for them.
• I can lean on PC and NPC bards (which exist in this setting) being able to do their legends and myths thing regarding magic items, which gives me a nice way to suggest what an item likely does without getting into game-mechanical details.
• High-level ritual spells that do a legends lore sort of effect could easily fill this role, but would be ridiculously expensive from NPCs even assuming a high-enough level NPC could be found and induced to give the PCs the time of day. This would be impractical for minor items, even for high-level PCs.

I'm currently leaning toward a combination of experimentation, visual FX of some kind, and some rare scrolls of a long-lost identify-alike spell to be found as treasure. Probably also bardic knowledge, but that would be more along the lines of "a bolt such as this one took down the Giant of Acadia in ages long past!" sort of unreliable hints. Pitfalls of these approaches or entirely alternate methods are very welcome.