SnapQuotes don't represent daily open-high-low-close summary data, but merely market activity as it has transpired up to the time of the SnapQuote (subject to delays). Therefore, it is likely that you'll want to remove SnapQuote data that has become outdated over the course of the day.
To clear SnapQuote data from charts and files, click "Clear SnapQuotes" from the Database menu.
Each SnapQuote overwrites the previous one, and your daily update using UA's "Get Data" feature will overwrite all SnapQuote data, so it isn't required that you manually remove SnapQuotes through this feature.
Note that this will not remove SnapQuote data that may have been written to export files. To remove intraday data from an exported file, re-write the file after clearing SnapQuotes.
Click here to learn about using SnapQuote data in export files.