scrapebox and public proxies...

whats up bhw... i have a question. i have scapebox, but i do not have money to buy proxies yet. so my question is. could i use public proxies to post comments or is that just a definite no? i just need help with this. i bought a proxy scraper just so i can scrape public proxies and use on scrapebox.

i manually collected proxy sources and always have around 200 google passed.
also you can find here lists of public proxies that works.

so you use public proxies to auto comment? that is mainly what i wanted to know. is it safe to do so, and wont have any bad side effects on my backlinks?