gas/oil, in in in filter , air intake

[300exjuggalo]

i was at my friends house yesterday, and i look at my filter at it was dirty. I decided to clean it, well i went to go take it off , and when i got it off, their was some oil, gas around where the filter hooks on, and some inside their, what does that mean? what should i do

thanks

Jason

[300exjuggalo]

plz someone, is it cause i had to much oil? or something, but it was just at the full mark :huh