We do suggest you choose a hashtag that is unique or use multiple hashtag terms that must be included in order for users to enter, to prevent unwanted entries. But if you are using old or commonly used hashtags, you may see recent uploads pull in.
Update 12/2018: Instagram is now only allowing hashtag uploads posted within the last 24 hours to be pulled into your campaign.
To remove the photos from your entry data completely, go to the campaign’s Submissions section. You can delete entries from the Entries section or the Submissions section. If you do it from the entries section, the hashtag entries will pull back in.
If you want to delete them in bulk, you can do so by clicking “actions” in the Submissions section. It will allow you to bulk action 50 entries at a time. The first step is to block the photos. When you block photos, it does not delete them as an entry, but it does remove the photo(s) from the gallery.
After you block the photo, you can leave it at that if you still want to have access to those entries in your data. However, if you don’t want the data, you will need to click on the “blocked” tab. Once there, click actions again and you can delete the photos in bulk (50 at a time).
If you only want to do one photo at a time, it’s a very similar action but instead of clicking the action tab, you’ll just select the “X” icon to block the entry. Then you can go over to the blocked tab and delete it individually as well, just by selecting the trash can icon.