What is the etiquette/procedure around dropping stuff to charity shops?

[MsFogi]

I've got loads of boxes of (very decent, saleable) stuff to donate but I have no idea how this works - do I just go into a random charity shop and drop a box by the till or do I need to wait to get it checked/talk to someone or something else? Can someone tell me how it works?
And I have loads of boxes (been meaning to drop off for ages but haven't got round to it) would I be better off dropping to a couple of shops or dropping to lots of different shops?
All insight gratefully received!

Local to me Oxfam and Barnardos both take rags - the DCs' socks with holes in/unpaired, scraps from my sewing. I put them in a plastic bag clearly marked RAGS and hand them in to the till.

They take your details and give you a Gift Aid ID. Everything from your donation bag gets a barcode printed out and stuck to its price tag linked to your ID, and when it's sold the cash from the sale will be notified to the Treasury attached to your name to reclaim the giftaid. You may also get an email from the charity saying "we raised 13.45 from your donations"

BHF also take rags.

One heartfelt plea, please don’t donate incomplete jigsaws. No one wants to finish a puzzle only to find one or two pieces are missing. The last two I’ve bought (from the shop where I volunteer) had 1000 pieces. One had two pieces missing, the other was one short, although there were 1000 pieces, one was from a completely different puzzle. 🙁

British Heart Foundation will take electricals and white goods too, they'll collect if you've something bulky or lots of stuff.

There are two large shops with donations centres near me that have parking outside and you can just take in your donations and leave them in a trolley, I usually go to one of them rather than a small shop.

If you're not a taxpayer it's no good. I used to have Gift Aid cards for about 6 different charities, but when I retired they told me they wouldn't get anything back on my donations.

Lots of useful charity shop knowledge on this thread!

I usually go in and ask them if I can drop off whatever I have. It's usually clothes and books in my case. They then tell me where to leave it and often there's someone in the back who asks what's in the bags and I tell them. The only time I've had anything other than "thank you, leave them there" is when I brought in loads of old toys which they asked me to empty into one of their baskets. Not sure why that was.

(btw when I say "old toys" I mean old to us and dcs had outgrown them - they weren't manky old things I swear 😂)

@IWonderWhereThatDishDidGo thank you for donating. Toys sell really well, we clean them up when necessary (quite often) and it’s lovely to see parents buying something they might not afford if new.