I have an 04 rx8 and I'ts in the garage for the winter, i went to check the oil and the dipstick had a light green whitish sludge all over it. So I changed the oil wait afew weeks then ran it and checked it again and its still there. Any idea on what it is, or how to get rid of it? thanks would this work oil catch tank.

 

sludge on the dipstick is normal for cold climates
https://www.rx8club.com/series-i-trouble-shooting-95/strange-gunk-oil-dipstick-info-questions-49652/
there is no 'fix', the only thing a dealer can do is modify the dipstick to hide the gunk. When it warms up it will go away till next year.

 

... in addition, keeping it garaged and running it only occasionally is greatly contributing to the gunk. Take it for a long, hard (high rpm) drive at least once a week and you'll 'cook' most of the condensation out. I saw this at its worst the first winter I had it since I was still breaking the motor in and couldn't yet drive the snot out of it... the last two winters I've barely seen any gunk at all.