Clean your fenders! All this crap came out of my 92 today. Complete with wasps nest!

 

Nasty. Did my cabin filter last year it was bad, but not that bad.

 

Yes I just cleaned out mine, and got a pile very much like yours, and I made sure to use anti seize on the bolts when I put it back together.

You should also consider undercoating the fender and the body.

 

Undercoat the inside of the fender? Hmmm...

 

I have undercoated the wheel wells, but for the inside of the fenders I find that a good cleaning and coat of wax works better. The undercoat is more grippy and leaves and stuff tend to get stuck easier.

 

How many bolts do I need to get to have the fender off? I know there's 4-5 of those plastic ones on the inside.

 

nah, don't take the fender off. just remove the bottom of the fender and pick the ---- out.

I think its like 3 bolts. 2 in the fender well and 1 on the other side. but it depends on if you have the stock splash guards or not.

 

Was this something you added to the cowl air intake?

 

different car completely. There is no cabin air filter in the miata.

 

Wouldn't make much sense in a convertible eh?