Here's a bash one-liner to copy the raw text from a LaTeX file. It strips comments (be careful if you use % in your text), removes newline, thins whitespace and finally pipes to the keyboard.
cat abstract.tex | sed -e "s/%.*$//" | tr '\n' ' ' | sed -e "s/  */ /g" | sed -e "s/^ //g" | pbcopy
If you're issuing this from vim then you need to escape the % sign:
    cat abstract.tex | sed -e "s/\%.*$//" | tr '\n' ' ' | sed -e "s/  */ /g" | sed -e "s/^ //g" | pbcopy