Search Engine Autocomplete

In search engines such as Dogpile, Mamma, Northernlights, etc. they have an autocomplete for previous searches beginning with the first letter. i.e. I type in “m” and the list comes up so I can choose previous search words starting with “m”.
How do I delete those lists? It seems they are different for each search engine. What files on the pc do I delete? I deleted all temp files, temp internet files, recent, cookies, etc. and they are still there. Are those kept at the search engine site?

Thank you