Hi Matt,
we operate a FDR/WDR/CC business downunder.
If 'they' have the ability to FLUSH the carpet, I would suggest that that is the best course subject to a few things.
Try and determine the type of products burnt to indicate the dryness or oiliness of the soot. If its a dry soot, vac really well yourself regardless of who else has vacced and then go for it, you have nothing to loose.
However if its an oil/fat fire, I would strongly recommend HWE even if you then follow it by encap to control any wickback. Also do a walk through and get a gauge on the odour level and other soft furnishings. If theres a strong odour, will all other soft furnishings be cleaned? Don't forget the 'sink' effect with fires.
eg I recently cleaned an old worn threadbare wool axminster carpet on jute backing where the weft fibres were coming loose. Clients didn't have replacement cover but it was moderately soiled from a fat fire. Kitchen, family, dining, and lounge were all open plan so moderate soiling all the way through.
Because of the factors involved with the condition of the carpet, there was no way I was going to be HWEing that carpet. I didn't relish the thought of replacing her carpet on MY insurance policy. I cleaned it with the Mex and Releasit Encap clean DS but rather than dropping it on the way up and then scrubbing on the way back, I just continued to trigger it on and off all the time keeping a very light foam in place without over wetting it. A couple of ace fans to speed dry and it really cleaned up bright without any odour.
That is the exception I would think for and oily/fat fire residue.
If it is a light to moderate fat fire, you could try the above and even include a bit of OP to absorb some of that residue. If you don't have OP (which I don't either) you can get bonnets and run them under a rotary if you have one. I picked up some CD bonnets (don't ask, I just did
) they are the really thick 2" cotton and they absorb like crazy. If I'm doing an encap with the rotary and FPPads, and its just a bit gunky in some areas, I'll run the bonnets over those areas and they really brighten up.
My preference where possible is to vac, prespray with a good detergent(sometimes a heavy duty detergent is required. I've even had to use Prochem UltraPac Renovate wall cleaner sometimes), scrub, RX20 with HOT water and then speed dry.
If you have any more questions, feel free to drop me a line with more info on fibre types, soot type, level of soiling etc.
Regards, John
John Middleton
Carpet Pro Ltd
Palmerston North
New Zealand