brake bleeding help

[astrocowboy5 at hotmail.com (Jonathan Mohan)]

ok every one is telling me to just bleed out the whole system but if i do
that before or after i change the brake lines wolnt i have a huge mess on my
hands?

i was thinking i would empty the system using air pressure than i could
change the lines and calipers and than bleed in the new ate blue.

am i wrong in my thinking or can i change the lines with out getting brake
fulid every ware some other way?

thnaks
Jonathan