There are patterns that can be used in search of editable content, such as:
"founded" (incorrect unless you are talking about foundations).
"Ho do I can...?"
"Do you can...?"
These ones came to my mind days ago and some search results show hundreds of pages with unexperienced writings in titles, questions and answers in StackSites that mix different writing contexts (code and explanations). The list can be endless and goes far away from common slang. Described and similar patterns are useful to find editable content and some of such patterns could make a topic hard to find. Anyone can use this to give a hand in cleaning and earn some reputation in exchange. However results and posibilities lead to another concern: set aside editable content and focus only on Editworthy content. Most of results are poor quality entries that go beyond grammar: they can be Old, obsolete and lazy writings for example. Edition, queuing, revision and approval of such stuff lead to its revival on main page, requesting unnecessary attention in present time and then requiring moderation, involved reanimators advise and voted deletion; rather than actions regarding site main drives: New Questions and answers.
These patterns are also the easy ones. Remembering my first School MS Word homeworks I recall long sentences that were hard to conceive their suggested corrections. Long patterns use to fall in semantic issues (and even far away, streaking the
unclear what you are saying area), but their appearance is still signal of unexperienced writing, and its search and automated analysis is still a subject hard to conceive and load into cpu memory in a worthy way.
If there's already an autocorrect bot, it will then need to update its directives and do its duty silently, at least with short and easy (typos, misconceptions, slang) patterns. All these may become a subject of study or community filled data to make some more automated usefull cleansing.
Last but not least to say: For recommended and non automated (member side) help, editworthy entries migth be searched and found using unexperienced traces along with good quality potential or actual presence in despite of its grammar (upvotes or fluent/rich explanations/feedback/activity).