Just got the tip from a buddy of mine who fixes hit cars, tried it and it worked. Thought I would share. Worked wonders on a dirty 2008 rx350.
Picked up some super clean at wal-mart (10$ US) for a big jug, and a dollar store spray bottle.
For the leather, mix 4 parts water (800ml) and 1 part super clean (200ml) in a spray bottle (I used 1L spray bottle). Do not put too much super clean in the mix or it will stain the leather!!!
Spray all over leather car seats, let sit for 20 sec and then immediately wipe down with a micro fiber cloth (I use the yellow ones from Costco). The go over with a sponge with just water. Then let dry. All the nasty stuff, dirt, coffee stains,etc on the leather seats will be gone. I tried dish washing soap, spray nine,etc and they would not remove everything. This super clean stuff is a monster. Then spray down with leather conditioner (I use the McGuire stuff, also from wal-mart). Your dirty and nasty seats with be good as new!
Fir the carpets, you can use a stronger mix. Although the spray bottle mix above works too. same, spray down the carpets, let sit and then go over dirty areas with a micro fiber cloth. Then vacuum the wet carpets with a shop vac. Salt stains and some mud/dirt all gone.