i agree with the coke for cleaning certain stuff, i use it mainly on motorcycle jets that have blocked after been sitting for a while
I also have a dishwasher in the garage running on water based degreasant, i have the 25L drum on top with the return going in the top, the supply going from about 4" above the bottom of the drum so theres some sediment area if any, that thyen goes to a pond pump which goes into the supply port of dishwasher, all in all a pretty handy heated parts washer, dishwasher was £10 off gumtree, pump was £8 of ebay + degreaser was £19 for 25l of concentrated which i diluted
On topic i have known many people putting a dishwasher tablet in the cooling system for a day then flushing next day