Chassis Paint Job for Winter

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Just about to start Hammeriting chassis for winter, after spending some time underneath it all seems accessible apart from the sill area(both sides). Advice seems to be to drill out rivets to get access,does anybody know a less destructive approach?

[ticker]

Thanks for the advice guys, sills off it is then!

What is this POR 15, and where can I get some? (Halfords?)