Flock of Greasy/Oily Stringfoot Pigeons-Advice Needed

I need advice on quantity over quality of assisting this flock-

There is a food truck park where about 25 pigeons live. About half have stringfoot of varying degrees, and most cannot fly due to being covered in some sort of thick grease/gel

I rescued one (will try to get photos), but the process of removing the grease to enable flight, along with the stringfoot, takes a while. I only have till October 23rd, and only one carrier to keep visiting that flock

I'm unsure if I should prioritise removing the stringfoot for helping a larger quantity or attempt grease removal + stringfoot for a few. Once the single carrier is occupied for grease removal and recovery, I cannot capture more for stringfoot removal alone

The grounded pigeons are otherwise safe in that food truck park, I believe, not many dangers as they are in a gated area

The trucks are non-mobile/permanently stationed, and I haven't seen cats around when visiting.The pigeons actually sleep under the trucks at night, sadly

I may only be able to get 2-3 more or so if I go the quality route