Bad idea, period!
Three reasons I can think of:
-needles dull as soon as you use them.
-all kinds of pathogens grow on the needle as soon as you draw out and especially as you wait. Cleansing the needle may kill of some pathogen but not all, some resistant to alcohol may still be on the needle.
-needles are cheap, they're less than a buck per needle and why risk your health by not trashing after the first time?