You have to be thorough. You cannot delete a bogus temp, only replace it. So, assuming you have some other historical source to determine what the value should be and when that was, replacements will make you feel better, but are not necessarily correct.
Having said that, replacing a bogus high for the monthly summary with a real value will not automatically correct the high for the year, so be prepared to update all necessary columns on the live data summary table. You might also want to take a screenshot before you start, in case you mess up, but note that it will not catch the time stamps (see below)
Also remember changing temp should imply changing dew point. Likewise changing RH.
Finally there is a trap for you. When you click it suggest you can enter a new value. If you just that it will remain labeled with the time stamp of the bogus value. You may append a string like @yyyy-mm-dd hh:mm:ss to also change the time stamp.