In such case this trick will help you a lot. I use this to compare original and spinned article in a single document. By this trick we can know exactly which word is replaced with synonyms and whether the replacement is in correct sense or not.
You need microsoft word for that and it works in Microsoft Word 2007 and above.
1. After spinning the article, open blank word document
2. click on review tab
3. click on compare icon
4. "Compare Documents" dialog box will appear
5. Now browse and provide original document and revised (spinned) document files path and click on ok.
6. Now both the documents will open in a single document. Deleted words will be shown in red color and added words will be shown in underlined red color fonts.
By doing this you came to know whether replace content with auto spinning is replaced with corect word or not.
There is a accept and reject buttons on top icon bar. You can accept or reject the changes made by auto spinner.
This is the great way to compare spinned articles in a single article and do the necessary changes. It helps to create even more unique content.
Moreever Microsoft words inbuit synonym checker also helps you in great way to replace the words.