Sanding provides a relatively chemical-free way to strip paint from pine. You're not exposed to chemical vapors, other than the dried paint itself. It also helps smooth the wood down in the process; if you have a rough furniture piece, it may need sanding anyhow. Since anything but gentle sanding with a fine-grain sandpaper is likely to take some of the wood with it, sanding may not work for antique or fine pine furniture, especially since pine is so soft.
Chemical stripping involves using a varnish or paint remover to soften the paint so you can scrape or slough it off the furniture. Liquid removers allow you to remove one layer of paint at a time so you can expose older layers without touching the pine itself. Pastes work well for larger furniture pieces. They allow you to remove long strips of paint all at once. Using too much water with wash-away strippers can damage the wood grain on pine. Sanding with coarse paper beforehand speeds up chemical stripping.
Paint remover guns and heat guns allow you to heat up paint, destroying the film so you can scrape it away. You must scrape the paint immediately after heating the furniture surface. This option works if you're very skilled with a heat gun, as keeping the gun pointed in one area too long damages wood -- and will damage soft pine more quickly. Excessive heat results in browning or spotting.
Effectively stripping paint from furniture requires smaller tools and a bit of patience. Leave paint stripper on for 10 to 20 minutes when removing paint from legs, carvings or crevices. Don't leave the thinner on for more than 30 minutes, since you want to preserve the soft pine as much as possible. Toothbrushes, fine-mesh scouring pads and medium-bristle scrub brushes work well to remove paint without damaging the pine. Always rinse the stripper from crevices and recesses so it won't sit and ruin the wood.