Speaker cleaning and maintenance

To clean the cones I use “TAC cloths” from a company called Rust-Oleum. 
Www.rustoleum.com.au/motorspray

AG🇦🇺

After running my speakers through the car wash, the sound was a little watered down. 

Hot and dusty where I live.. Vacuum with a brush attachment. If I see surrounds getting too dry I’ll treat them. I only use Silicone or BR surrounds so silicone is the best treatment on the surround, not the binder (glue). I apply the silicone with a lent free rag. I have 50 year old BR surrounds and 75+ on cloth/wire surrounds. They will last another 75 years.. The suns UV are the killers..

I quit dong the car wash thing.. Every time I let them dry out... :-)

Regards

every easter i load my speakers in the bed of my pickup truck and run through a brushless car wash

make sure it is a brushless wash, you don't want swirls on the finish

I'd try pinch roller rubber renue before any car crap.  But I'm not gonna.  
Audio NOT auto.

Cover the whole speaker in foam, use Griot's Garage wash mitt, rinse with reverse-osmosis purified water and blow dry. No wait that's the car. Wash both sides with Walker Cleaning Solution, then Walker Enzyme, then two purified water rinses the last one vacuumed off with the, no wait that's records. Dang. Okay, okay got it now: soft brush furniture attachment on the vacuum cleaner! 

The reason I forgot is I only did it one time, years ago.

Cleaning speakers... OMG, I didn’t think that was a thing. I have not cleaned a speaker in 50 years of owning high end audio.

" car rubber protectant to the surrounds"

If you want to go that route, I`d recommend 303 protectant. Stay away from anything with sylicone . I get the impression that you leave the grills off your speakers. If so, the cones will collect more dust and the surrounds may discolor from the light. I leave the grills on, to protect the drivers, and to save myself from doing the extra work of cleaning.
To vacuum the drivers: use an adjustable suction (lightest setting) and hold at sharp angle to cone, not perpendicular, and brush lightly with natural hair brush. I only do this, if I had bought the speakers used and needed dusting.

my rubber surrounds are a bit discolored and I found a few videos about applying some car rubber protectant to the surrounds, anyone had any experience?

Doing nothing is best or use Swifter.