Clare, there is a number of threads on this which might be of some help.
I would not wash them all together. For example, if you have used some to remove wax and others to remove plastic polish you could get some crossover. I hand wash-soak first to remove most of the gunge before mixing them in the machine. Maybe I go a little over the top :nixweiss
Dont put the temp to high, I use 40-50 with no problems. Never use a conditioner as it will ruin the fibres. Oxi-Clean is a good product, also good for cleaning carpets and seats etc.
Steven