Goot

The first time is gong to be tough. I clean my wheel wells with every wash, so it's not that tough for me anymore. I use the same car wash soap leftover from the truck and a sponge. Comes out perfect every time.

Nynd

Never tried the undercarriage spray, but you can use a soft brush with a bucket of soap when washing or I use the black Vinyl spray for the black liners (none fabric type).

hinglemccringleberry

Powerwash, then rub the well liners down with a mix of water and another product on my shelf, either 303 or Stoner trim shine. Sometimes I just do water and wipe. Wiping them down is the most important part, makes a huge difference. Sometimes cleaning the wells like this makes my truck look clean all by itself even if I didnt wash the rest of it..

2015rubyFX4

we own an automotive detailing company and we use diluted simple green (the regular green version) and spray it on.. Use a brush if you have too (but very rarely do I have to) Then blow dry and spray with stoners trim shine (non aerosol) after. PERFECT.

BTW= simple green will NOT hurt plastic, especially diluted.. Its absolutely not true about it damaging plastic. Do not worry. We have used it on hundreds of cars over the years in our detail business. Its one of the most gentle but effective cleaners you can buy.