Great thread. I've done limited beauty treatmehts on my Dooney handbags.
But here is what I've learned:
AWL should not be treated with any commercial cleaning or water proofing
or conditioning product. The original AWL was created by shrinking the leather
to close the pores. Any commercial product could undermine the leather, change it's
appearance and inhibit its water resistance.
The smooth brown vachetta leather trim on Dooney handbags
(pebbled leather, etc) can be conditioned. I use Apple brand conditioner
and it helps to prevent water staining.
The natural, un-dyed smooth vachetta leather will spot and stain.
My bags last 1 use before I have an issue from even 1 drop of moisture.
I don't have any rehab or prevention tricks.
I've conditioned Florentine handbags (midown or darker colors)
using Apple brand conditioned. Use product sparingly and don't
over condition. Test leather in a hidden spot first to make sure
there is no color bleeding.
Keep leather treatments and conditioners off any area with
stitching or that might have glue (like strap attachments).
These products can weaken the thread and glue and
handles and trim can end up falling off if too much
conditioner is absorbed. This is sometimes an issue
with preloved handbags.
I also use white cloths (wash cloths or microfiber cloths,
even old clean white T shirts)
when cleaning, conditioning, or even buffing a handbag.
That way I avoid any color transfer and also get a better
handle on what might be coming off the bag too
(color, dirt, etc.).
It's not a good idea to 'dunk' handbags to rehab them.
Vintage bags were made differently and not lined.
So maybe this technique was ok. I don't know.
But modern bags are lined so we have no visibility
to what might be used to help the style and maintain
the structure of the bag. There may be layers of
different material (buckrom? cardboard? who knows?_
submerging the bag in water could ruin it.
If the lining can be pulled out of the bag it can be spot cleaned.
But again, don't soak it and be on guard for color bleeding
which could damage the outside leather of the bag.
Remember, what works on one brand, might not work on another.
And different collections within a brand may need to be treated differently,
or even the same style manufactured at different times, or different colors.