How to copy a column with conditional format by "value" - Libreoffice 4.1
AFAIK, there's no perfect solution for this kind of task. The best practice depends on the contents of your sheet - especially, if you want to keep formulas, too.
Generally, you can drop the rules regarding conditional formatting by saving the sheet as HTML, and re-loading the HTML into Calc. Of course, this will drop stuff like functions, too - just keeping the calculation results. It will also drop style sheets.
If you want to keep, e.g., functions, you may proceed as described, but keep the original file. Now, copy the imported HTML, and paste just the formats, keeping the original cell content. The result should be a Calc sheet with original cell content and non-conditional formatting. Maybe overkill again, but this depends on your needs...