At the moment there is no property in the RecycleItem properties property that states the date/time the item was deleted, or a date/time the item will be permanently removed if not restored.
This relates to the properties returned from the properties property from the RecycleItem class, see current documentation here.
A deleted date/time or an expiration date/time or both would help to send notifications for items that are about to be deleted within the next day or two.
Below is a list of current properties returned for a Shapefile item.
id
owner
created
isOrgItem
modified
guid
name
title
type
typeKeywords
description
tags
snippet
thumbnail
documentation
extent
categories
spatialReference
accessInformation
classification
licenseInfo
culture
properties
advancedSettings
url
proxyFilter
access
size
subInfo
appCategories
industries
languages
largeThumbnail
banner
screenshots
listed
ownerFolder
protected
numComments
numRatings
avgRating
numViews
scoreCompleteness
groupDesignations
apiToken1ExpirationDate
apiToken2ExpirationDate
contentOrigin
lastViewed
inRecycleBin
