I got a few tips I've picked up in the last few years
use "house" copper wire tightly wrapped around the head of a hammer or mallet and then covered in electrical or plumber's tape to save the handle in case of misses.
a layer of RTV around the grip of a handle on hammers is a chemical resistant anti-slip coating that lasts forever.
truck bedliner is awesome in the pan of tool carts to prevent scratching, rust and it resists most chemicals even brake fluid, also stops things from sliding around and helps you locate shiny tools and parts better and its easy to clean.
old, cheap or broken screwdrivers are perfect for making custom picks or hooks .
hockey pucks make good resistant seal drivers for axles etc .
trunk springs can be fashioned into caliper hooks when cut with a cutoff wheel and bent in a vise. A squarish "s" with one hook bigger than the other works best .
tackle boxes are good bolt/nut, fuse/bulb or cotter pin organizers , usually found cheap at yard sales too.
radio flyer wagons are very good "junkyard carts" for tools and parts.
baking pans and cupcake trays from the dollar store are good work trays and bolt/nut holders . Spraypaint helps keep them rust free .
pledge sprayed over tools and toolboxes helps stop corrosion and isn't very messy . Also works good in lubricating and keeping air hose fittings working smoothly .
a fast resource for lubricants viscosities and capacities is Amsoil's website .
Old pots and pans are great to dunk or bathe parts and to hold bolts and other parts, thick pans without the handle are very flip resistant.
old metal file cabinets are good for storing flammable chemicals and gas cans .
old license plates are really good pliable heat shields.
the cement mixer pans from the hardware store are good for drip pans that can hold a LOT of fluid and are slim enough to fit under a car or truck , very thick and resistant too. I use them for oil changes at home.
those extra forged wrenches that no longer work because the open end has opened too much or other defect can be fashioned into an awesome knife with a finger hole or lanyard hole by using the box end .
old steel rims make awesome grills.
you can bleed brakes or clutches by yourself by using a large brake bottle with a vacuum line going from the bleeder into it , and a small full bottle upside down on the reservoir to make sure you don't run out of fluid .
monofilament wrapped around a nut and then tightened on the bolt makes your own nylock nuts.
the thick plastic windshield wipers can be filed and made into interior prybars .
seatbelts make good straps and even hold the weight of an engine and transmission or rear end , especially whole ones with the bolt eyelet still attached.
A large sturdy vise can be used to press bearings and u-joints in or out in lieu of a shop press.
scrap 4x4 and 6x6 pieces can be found real cheap at the big hardware stores usually nearly free and they will cut it to size for you.
marking macpherson struts on the outside and front with a tire crayon by making a line straight down the spring and top bearing/mount will help you put it in easily and correctly when installing them.
a piece of glass works best for mixing epoxy, you can see when its mixed all the way and can be cleaned with steel wool or wire brush ,and you waste less compared to using cardboard .