I had life happen to me and my canola-heavy honey in the flow frames crystalized (both in the cells and the bottom tubes).
Winter is coming and here in Canada we reduce to 2 boxes quite early so I removed them already, but how do I clean them up? I thought maybe hot water or something?
I’m ok with losing that honey, have way too much already anyhow 
Hot water should be fine, just don’t make it any hotter than 70C to save damaging the plastic.
If you did want to save the honey, you could try a simple “warming cabinet”. Some people just put a regular (not CFL or LED) light bulb inside a large cardboard or wood box, and put the honey super inside that for a couple of days. I guess you could also put the light bulb inside an empty super on top of (or under) the Flow frames and put a lid on top to keep the warmth in. I would put an inner cover between the light and the frames though, as UV light makes the Flow plastic brittle over time.
Will a hair dryer liquefy the honey?
This is from our FAQ- https://www.honeyflow.com/faqs/cleaning-frame-maintenance/p/67
We haven’t found the Flow™ comb itself needs cleaning if it stays in the hive - the bees do a great job of keeping it clean. If you remove Flow™ Frames from the hive and store them for a while they may need cleaning. You can do this by using hot water (just hot enough to melt wax). A hot water hose is good. Set the Flow™ comb to ‘cell open’ position, this allows the water to run quite easily through all parts of the frame.
We have designed the honey trough at the bottom of the frame so that any remaining honey can drip back into the hive for the bees to use. If the honey leak-back gap remains clear this works well; however, if the bees block it up some honey may remain in the honey trough after harvest. Clear the leak-back gap prior to harvest and inspect the honey trough. If the honey trough is dirty it can be cleaned from outside the hive using a bottle brush or something similar.
If you are storing your Flow™ Frames for any length of time outside the hive, ensure they are kept away from the light as the Flow™ frame plastic is UV sensitive. Store the frames in a cool, dry, dark location.
https://www.honeyflow.com/faqs/does-the-honey-crystallise-in-the-flow-frame/p/69
If honey has crystallised in the Flow™ Frames, you have two options:
Wait for the bees to remove it: Attempting to harvest the honey will have disturbed the comb a little. The bees will likely remove the crystallised honey to repair the comb.
Remove it yourself: The frames will need to be removed from the super and soaked in warm water to soften crystallised honey.
If you are in an area that is prone to crystallised honey, we recommend harvesting as soon as the honey is ready.
Might get hotter than 70C and damage the plastic, plus if it is capped, it would melt the wax and make an interesting mess… 
I just wrote this before in another thread, so apologies, but I’m just pasting it here.
This is from our FAQs page - https://www.honeyflow.com/faqs/p/22?tag=22
Maintenance & Cleaning
https://www.honeyflow.com/faqs/cleaning-frame-maintenance/p/67
Cleaning and Flow™ Frame maintenance
We haven’t found the Flow™ comb itself needs cleaning if it stays in the hive - the bees do a great job of keeping it clean. If you remove Flow™ Frames from the hive and store them for a while they may need cleaning. You can do this by using hot water (just hot enough to melt wax). A hot water hose is good. Set the Flow™ comb to ‘cell open’ position, this allows the water to run quite easily through all parts of the frame.
We have designed the honey trough at the bottom of the frame so that any remaining honey can drip back into the hive for the bees to use. If the honey leak-back gap remains clear this works well; however, if the bees block it up some honey may remain in the honey trough after harvest. Clear the leak-back gap prior to harvest and inspect the honey trough. If the honey trough is dirty it can be cleaned from outside the hive using a bottle brush or something similar.
If you are storing your Flow™ Frames for any length of time outside the hive, ensure they are kept away from the light as the Flow™ frame plastic is UV sensitive. Store the frames in a cool, dry, dark location.
Does the honey in the bottom of the Flow™ frames ever go mouldy, ferment or crystallize? If so, what can I do about it?
We recommend cleaning Flow™ Frames at the end of the summer, after harvesting is finished for the year.
This is easy to do without removing the frames from the super or the super from the hive. You can squirt water into the trough and then let it drain out.
If there are still signs of dirt, mould or crystalised honey, you can use a bottle brush to loosen it and then wash out with warm water.
https://www.honeyflow.com/faqs/do-i-need-to-clean-the-flow-frames/p/87
Do I need to clean the Flow™ Frames?
Apart from the trough at the bottom, you don’t need to clean Flow™ Frames unless you detect disease in them. You will need experienced beekeepers to give you advice on disease prevention and response for your area.
The plug for the honey collection trough is designed with tiny grooves that allow a bee lick up any residue honey that collects behind the plug. Sometimes the bees block these grooves with propolis (a resin bees use to plug any holes in the hive) but it is easy to clean this out by removing the plug. We haven’t experienced propolis build-up in the frames themselves.
https://www.honeyflow.com/faqs/flow-frame-sterilisation-irradiation-disease-control/p/145
Flow™ Frame sterilisation / irradiation / disease control
Heat treatment: Flow™ Frames can handle hot water up to 70˚C.
Chemical treatment: The plastics chosen have good chemical resistance. We will be testing various chemicals to evaluate this soon.
Irradiation: We have tested the Flow™ Frame parts with multiple doses of 15kGy gamma rays. We load tested the irradiated parts and tested them to destruction. The results were: 1 dose had little effect; 2 doses had minimal effect; 3 doses made the plastic significantly more brittle. We will be testing further to see if this causes any failures, but at this stage we can say the Flow™ Frames can be irradiated twice at 15kGy.
Could you place them in a warm shower in the bath room to clean up the frames once the honey has been extracted?