For those too timid to use their wives washing machine for this.... I just re did mine,and i used one of those back rectangular 21 gallon plastic mixing tubs, I bought these at home depot, they are about 20 some inches wide and 30 some inches long and about 8" deep. https://www.homedepot.com/p/Large-Mixing-Tub-26101/301943160 The mats don't fully submerge, unless you put at least 12-14 gallons of water in there. Use two (maybe even three) bottles of dye for 12 gallons, and move the mats around and flip them over every few minutes for 30 minutes. Follow the instructions of the bottle, use hot water. I did mine in the yard to keep any mess out of the house. I redid my mats because the first time I did them in the washer, they didn't come out completely uniform, they look much more uniform now. My mats were originally a light tan color, they are now a medium charcoal grey. Doug
I don't post with a smart phone so i don't take pics of everything. Sorry. Trust, me, they turned out fabulous. $10 of Rit dye,and that $12 plastic tube, $25 for nice matching color mats to the carpet. After I was done with the dye bath, I rinsed them with a garden hose until the water ran clean, like the directions say, then let them air dry for about 3 hours over acouple lawn chairs in the sun. That was in AZ, if you live someplace humid, the drying may take longer. Doug