From A Sketch of the Life of Georgiana, Lady de Ros (1893)

1836.—George IV had, from the time he was quite a young man, been in the habit of carrying about him a douillette pocketbook, into which he used to put money, letters, trinkets, miniatures, and any of the numerous fans, odd gloves, locks of hair, and similar keepsakes which he was always adding to his stock from all quarters. As soon as his pocket-book became full, he used to put it away in a drawer without ever troubling himself to examine its present contents or take out whatever money it might contain, mixed with the miscellaneous articles. Whenever he thus put away a full pocket-book, he took another to replace it from a great stock of new ones he kept by him, and this, as soon as filled, was laid by and replaced in like manner. At the time of his death it devolved upon the Duke and another to examine the personal effects of the King, and accordingly they had to look over the contents of a whole chest of drawers entirely filled with these pocket-books, filled and stowed away by the King from the time he was a young man. When the Duke first looked at one of them, and found the toys it contained, he was about to have the whole stock burnt, but some money accidentally fell out, which led to a careful scrutiny of others, and they actually collected in various sums no less than ,£10,000 from these pocket-books, after which they caused them to be destroyed with their less important contents.

Note: Between them, Wellington and Mrs. Fitzherbert consigned most of Prinny's private items and papers to the fire.