The keyboard & mouse were easy to clean - I removed the electrical bits and poured boiling water over the cases. The rug and trousers were not so easy.
The usual method for de-waxing carpets found on the internet involves picking at them with a knife, maybe after chilling with ice, then applying heat & absorbent paper. I didn't think this would work on my rug because a lot had soaked in deep.
Washing-up liquid (detergent)
An empty food-can (and can opener)
Step 1: Preparation
Apply a little detergent to this area, which should help wet the fibres and allow water to penetrate rather than roll-off.
Using a can-opener, remove the other end from a empty can (sweetcorn in this case) to give you a steel ring. This will help guide the hot water you are about to apply to the back of the rug.
Place the rug over a bucket, preferably in a bath or over a surface which will not be harmed by water. Level and flatten the rug on the bucket. In this position water should be inclined to move straight down, rather than to one side.
Step 2: Wax Off
Pour hot (just boiled) water into it - see picture - be careful and notice from the second picture that I'm keeping at arm's length away from the water.
I used 1.5 Litres, and it would have been ~95oC.
Some of this escapes to the sides, but a high-handed, rapid pouring drives hot water into the rug, splashing is contained by the ring and detergent-foam.
Dry the the rug as you find convenient, at the moment mine is draining in the bath after a total washing. I suppose I'll hang it out later.
Step 3: The Results
As documented elsewhere, place a sheet of absorbent paper over the waxy area and apply heat with pressure, the function of a hot pan should be obvious.
One other remaining patch required two hot water treatments, but was similarly removed.