On really bad vehicles it is easier to pull the seats out. You can then clean starting from top to bottom. You have more room to work.
On power seats you will need to leave everything on the seats plugged in to get access to the bolts. Do both sides first before disconnecting the battery. Be careful with the plugs. Note how they release first. Do Not pull on the wires especially air bag seats. Many manufacturers only sell complete harnesses as it is not recommend to repair. They operate on low voltage signal. Too much or tool little resistance can trigger the light.
First make sure if there ARE air bags in the front seats. The battery will need to be disconnected before unplugging to be safe. Also if you turn the key you may trigger a fault code once unplugged if the battery is on. You will then at that point need to know the process to reset (ie Hondas) (been there done that

) You also need to make sure you have the radio code if applies.(also been there done that

)
Make sure you lay something across the jambs when pulling front. You do not want to scratch the jambs. Also be aware where the seat tracks are at all times. You do not want to pierce a door panel. Same with the back know where any brackets sticking out are. Place the seats on scrap carpet so as not to mark any material while on the ground. This will also make it easier to clean them vrs climbing around them inside. Carpet too will be easier to clean thoroughly. Depending on the type of vehicle you may need a set of Torx bits for seat belts or even seats.
When assembling make sure no wires are crimped by the seat and all connections are plugged in properly if applies. This is before you tighten the seat down. Make sure to start all bolts first.(front two then back two depending on the order you took them out)
If you know all this already good.
I was explaining my response as for someone who may have not tried this approach yet. Just want everyone to be safe. There are a few body shop guys around who have found hidden wire damage the hard way.
Just a suggestion I've found time wise it does save on really nasty jobs just pay attention to those details.