To help with your Googling, this technique (removing the extreme observations) is known as "trimming". You can use PROC UNIVARIATE to get the trimmed means. You can read about some of the statistical shortcomings that are associated with trimming (or "Winsorizing") data,
If you are trying to perform a robust ANOVA, the best way is to use a statistical procedure that is not sensitive to outliers. There is an example in the SAS documentation that shows how to use PROC ROBUSTREG to perform a robust ANOVA. By using PROC ROBUSTREG, you will not throw away good data unnecessarily, which is what happens when you automatically discar the minimum and maximum values in each group.
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