I use warm water with washing up liquid and a good stiff brush. Don't think there are any shortcuts. If that bowlful is all of them it won't take long. Then just put them outside to dry off.

Thanks Steragram- there are more pots than you can see between 35- 40 in total! Lots of tiny terracotta pots- would they be good for transplanting seedlings ? I worry the terracotta dries out the soil?

I use, and wash, a lot of clay pots. I have an open top rainbutt so I thread the pots on a cord and suspend them in the water for 24/48 hours. The slightly acid water loosens any lime scale and softens any compost remains. They are then taken into my potting shed sink of cold water, brushed clean, dipped in a bowl of disinfectant and placed outdoors to dry. I have been doing this for years and it works for me.

You hardy soul Bulbaholic - I use warm water! I end up with towers of pots on both sides of the utility room sink and an array of them outside drying on the patio....
Fortunately limescale is not a problem here. Your water butt idea is brilliant!

Mr B do you use Jeyes on your pots...

Jeyes is often recommended but I use a cheap disinfectant from the supermarket and slosh a lot in the water. Jeyes is much more expensive but the main reason that I do not use it is because it STINKS and the smell is absorbed into the pots.
Do you remeber that a couple of years ago we were discussing ways of keeping badgers out of gardens? The most popular method was to soak rags in Jeyes and hang them on the fence - certainly effective, but the smell of it!!!!
Stera, I try do as much pot washing in the summer when the water is not that cold. If I have wash in winter I have to admit to adding a kettleful of hot water!

Thanks Mr B, I do use Jeyes for cleaning the G'houses and washing down in the dogrun and my outside drains but have always been a bit unsure for my pots and trays, I am weird as I actually like the smell, yes now you have said that I can remember the badger blog, if I remember it correctly we had a laugh about that one...

Bulbaholic- think I will try your water butt method and then give them a scrub. I have been given quite a few tiny ones- an inch or so wide at the top. Not sure what to use these for as the soil dries out so quickly? Thank you for sharing your cleaning tips.

I have a shelf-full of these very small one that I no longer use, Amsterdam. At one time they would have been used for pricking out seedlings but you are right, they do dry out very quickly and are high maintenance!