The natural detoxing I did when mercury toxic was mainly eating properly and adding raw foods. I did not do juicing, because I believe the fibre/skin and flesh of fruits and vegetables is necessary and helped things move through better also and was all part in helping toxin elimination for me.

Instead of saunas, I chose hot baths with epsom salts or sea salt and baking soda. (about a cup or more of each). And I'd lie in it for as long as I could without making myself woozy. At that time, I could handle this because my body sweated properly and eliminated a lot via the pores. This worked really well. I would shower off afterwards usually.

I found then that quality vitamin C powder (high dose) also helped me then and aided some toxin release, as did vitamin E and selenium.

And like you James, I did walking. I used my treadmill mostly and this helped me so much! I think I eliminated a lot of toxins and metals from this without even realising it at first. I was able later to increase the time and put the treadmill on incline, so I would simulate uphill walking (though not extreme).

Also, rebounding on a mini trampoline (rebounder). This stimulated my lymph as well and did a lot to aid toxic elimination. I alternated with this and treadmill.

The loofah mitt I did also.

Apart from that? I cannot recall what else I did, apart from sticking to a proper diet and chelation. I think they all complimentated eachother and aided me to heal from mercury at that time.