purple power is a lot cheaper then solvent. thats what i use in my parts washer, about a 50/50 mix of water and purple power. i have a fish tank heater in the parts washer and it works so much better then when its cold. most stuff i just let sit over night (unless its aluminum, purple power will destroy it if left to long) then hit it with a brush and rinse with fresh water.
solvent works so much better and faster but its also dangerous to have in a shop with welding, grinding ect.