According to some SEO Practices having long URL is not good.
Magento uses layered navigation and when you have lots of attributes then the URL becomes very very long.
I can not put an URL here because the moderatos say its too localized.
I just wanted to know if this is possible to fix using any kind of code?
As I am not an expert on magento or php, I can not provide any code because I dont even know where should I start looking for to fix this.
Somebody suggested editing filter.phtml and put rel=nofollow.
Is it a good practice? Is it recommended that search engines dont crawl those pages that are related to layered navigation?
Another problem they have is that the title and description its always the same.
Why don’t you read YOAST Magento SEO article?
YOAST Magento SEO