The Knopf Collector' Guides to American Antiques, GLASS, Volume 2, Bottles,Lamps & other Objects written by Jane Shadel Spillman pictures one in a dark olive green glass with a thumb rest on the top
{see photo of my quick sketch}. I sketched it from memory and left out one of the knops for a total of four on the original piece which would make it more in proportion to its base. She puts the date at 1800-1850. She feels they were used at room temperature as the tendency to crack would be way too high.
The one in the CMOG {50.4.489} evidently has a definite provenance from the Willington Glassworks c.1800-1825. No shaft really just a knob.
While I am no laundry expert, I believe early 19th century laundering methods went something like this: fill your metal tub with water, put it on the stand over the fire, heat it up, add your linen/whatever and have your cleanser close at hand, scrub like hell.
I would posit that the linen smoother would come into play right after the wringing out of the excess water and the linen/whatever was still warm and damp.
Is there evidence the one in the Corning from Willington Glassworks was definitely used as an iron/linen smoother? It says it's badly worn from usage. I'm just wondering how many linen items the poor person would have had to iron to make that amount of wear on it.
Mine is very worn in the central area at the bottom - the shine is worn off. But the rest of it apart from the odd scuff patch on the side of the base looks as though it were made yesterday. Yet I think it's 400 years old.
If I hold it with my thumb on what 'appears' to be a broken top, it fits very nicely.
I will look up the Shadel Spillman item if I can find it - thank you

I don't know if they were used on damp cloth to be honest. I mean ironing a long skirt with a stone with a handle is ridiculous to me. Especially a stone shape that wasn't flat at the base but curved. It would have taken hours. But to press creases or seams or smaller collars then I can see that perhaps yes,with the curve shaped bottom good so as not to snag surrounding material whilst pressing a small area. That said, it would have still been ridiculously unwieldy to have used the one with a handle to iron a seam. I mean ... really, to be honest I'm struggling to see how these could have been used as linen smoothers.
I can see how in medieval time a smooth stone might have been used hand held cupped in the hand. But not these heavy ones with handles attached.
Washing laundry was a very convoluted art. Heavy big materials, lots of cloth etc - various recipes in late 1700/early 1800s book talk about boiling rice, then removing rice, boiling the item in rice water, then pressing it but not with a hot iron etc. and that's just for Chintz or ribbons depending on which year and which journal you're reading.
I think what I'm coming to is that I think mine is much older than 1800s. And I think the Gribdae farm one is as well. They are a good match for what is in the Woodchester Glass House book but the book isn't a pattern book of course.
The Woodchester author wrote (published 1954) '
Various observers have considered them to be pestles for pulverising or grinding glass-making materials, and others have thought them to be linen smoothers for domestic use'. So there was debate in 1954 over what they could have been used for.
I can't find anything of contemporary times that describes these handled items as linen smoothers.